THE PUZ ZLIN G BEAUTY OF NUMBERS

258
THE P U Z Z L I N G BEAUTY OF NUMBERS Kiryl Tsishchanka [email protected] Department of Mathematics Knox College THE P U Z Z L I N G BEAUTY OF NUMBERS – p.1/41

Transcript of THE PUZ ZLIN G BEAUTY OF NUMBERS

Page 1: THE PUZ ZLIN G BEAUTY OF NUMBERS

THE P U Z Z L I N G BEAUTY OF NUMBERS

Kiryl Tsishchanka

[email protected]

Department of Mathematics

Knox College

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.1/41

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A little known verse of the Bible reads

And he made a molten sea, ten cubits from the

one brim to the other: it was round all about, and

his height was five cubits: and a line of thirty

cubits did compass it about. (I King 7:23)

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Bible 550?BCE 1 place 3

Al-Kashi 1429 14 places 3.14159265358979

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Bible 550?BCE 1 place 3

Archimedes 250?BCE 3 places 3.141

Al-Kashi 1429 14 places 3.14159265358979

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Bible 550?BCE 1 place 3

Archimedes 250?BCE 3 places 3.141

Zu Chongzhi 480?AD 7 places 3.1415926

Al-Kashi 1429 14 places 3.14159265358979

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Bible 550?BCE 1 place 3

Archimedes 250?BCE 3 places 3.141

Zu Chongzhi 480?AD 7 places 3.1415926

Al-Kashi 1429 14 places 3.14159265358979

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Bible 550?BCE 1 place 3

Archimedes 250?BCE 3 places 3.141

Zu Chongzhi 480?AD 7 places 3.1415926

Al-Kashi 1429 14 places 3.14159265358979

Machin 1706 100 places

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.7/41

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Bible 550?BCE 1 place 3

Archimedes 250?BCE 3 places 3.141

Zu Chongzhi 480?AD 7 places 3.1415926

Al-Kashi 1429 14 places 3.14159265358979

Machin 1706 100 places

Shanks 1874 707 places (527 correct)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.8/41

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Bible 550?BCE 1 place 3

Archimedes 250?BCE 3 places 3.141

Zu Chongzhi 480?AD 7 places 3.1415926

Al-Kashi 1429 14 places 3.14159265358979

Machin 1706 100 places

Shanks 1874 707 places (527 correct)

Bellard 1996 400.000.000.000 places

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.9/41

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Wallis:π

2=

2 · 2 · 4 · 4 · 6 · 6 · 8 · 8 · 10 · 10 . . .

1 · 3 · 3 · 5 · 5 · 7 · 7 · 9 · 9 · 11 . . .

Leibniz:π

4= 1 −

1

3+

1

5−

1

7+

1

9−

1

11+ . . .

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.10/41

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Wallis:π

2=

2 · 2 · 4 · 4 · 6 · 6 · 8 · 8 · 10 · 10 . . .

1 · 3 · 3 · 5 · 5 · 7 · 7 · 9 · 9 · 11 . . .

Leibniz:π

4= 1 −

1

3+

1

5−

1

7+

1

9−

1

11+ . . .

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π

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πTHE P U Z Z L I N G BEAUTY OF NUMBERS – p.11/41

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πTHE P U Z Z L I N G BEAUTY OF NUMBERS – p.11/41

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π

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π

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π

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.11/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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TOP TEN LIST

10. e is easier to spell than π.

9. π ≈ 3.14 while e ≈ 2.718281828459045.

8. The character for e can be found on a keyboard, but π can’t.

7. Everybody fights for their piece of the pie.

6. ln π is a really nasty number, but ln e = 1.

5. e is used in calculus while π is used in baby geometry.

4. ’e’ is the most commonly picked vowel in Wheel of Fortune.

3. e stands for Euler’s Number, π does not stand for squat.

2. You don’t need to know Greek to be able to use e.

1. You can’t confuse e with a food product.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.12/41

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−1= (−1)1 = (−1)13+1

3+1

3

−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.13/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.14/41

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−1 = (−1)1 = (−1)13+1

3+1

3

= (−1)16

·2+16

·2+16

·2

= (−1)16

·2(−1)16

·2(−1)16

·2

= (−1)2·16 (−1)2·1

6 (−1)2·16

= [(−1)2]16 [(−1)2]

16 [(−1)2]

16

= 11/611/611/6

= 116+1

6+1

6

= 11/2

=√

1

= 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.15/41

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DEFINITION:

Suppose that a is a nonzero real number and that m and n are

integers such that n > 0. Then

am/n = (am)1/n,

provided a1/n exists.

EXAMPLE:

(−1)2·16 (−1)2·1

6 (−1)2·16 6=

[

(−1)2]

16

[

(−1)2]

16

[

(−1)2]

16 ,

since (−1)16 does not exist.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.16/41

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DEFINITION:

Suppose that a is a nonzero real number and that m and n are

integers such that n > 0. Then

am/n = (am)1/n,

provided a1/n exists.

EXAMPLE:

(−1)2·16 (−1)2·1

6 (−1)2·16 6=

[

(−1)2]

16

[

(−1)2]

16

[

(−1)2]

16 ,

since (−1)16 does not exist.

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B C

A

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.17/41

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B C

A

D

E

FG

H

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.17/41

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B C

A

D

E

FG

H

K L

M

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.17/41

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PROBLEM:

A plane is colored blue and red. Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color. This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

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PROBLEM:

A plane is colored blue and red.

Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color. This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

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PROBLEM:

A plane is colored blue and red. Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color. This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

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PROBLEM:

A plane is colored blue and red. Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color. This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

Page 53: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A plane is colored blue and red. Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color. This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

Page 54: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A plane is colored blue and red. Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color.

This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

Page 55: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A plane is colored blue and red. Is it always possible to find two

points of the same color exactly 1 inch apart?

SOLUTION:

Think of an equilateral triangle with each side exactly 1 inch long.

At least two of its vertices have to be of the same color. This

proves that there have to be two points of the same color exactly 1

inch apart.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.18/41

Page 56: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 57: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 58: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 59: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 60: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

� � �

� � � �

� � � � �

� � � �

� � �

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 61: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

1 2 3

4 5 6 7

8 9 10 11 12

13 14 15 16

17 18 19

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 62: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 63: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 64: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 65: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 66: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 67: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

× ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 68: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

× × ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 69: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

-22 -8 -17

-23 -20 24 33

-28 19 -88 -9 1

-2 4 -54 -7

0 -42 5

× × ×

× × ×× × × ×

× ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 70: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

× × ×× × × ×

× ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 71: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

1 2 3

4 5 6 7

8 9 10 11 12

13 14 15 16

17 18 19

× × ×

× × × ×

× × ×

× ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 72: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

� � �

� � � �

� � � � �

� � � �

� � �

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.19/41

Page 73: THE PUZ ZLIN G BEAUTY OF NUMBERS

Math problems?

Call 1 − 800 − (10x)2 −sin(xy)

2.36z

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.20/41

Page 74: THE PUZ ZLIN G BEAUTY OF NUMBERS

Math problems? Call

1 − 800 − (10x)2 −sin(xy)

2.36z

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.20/41

Page 75: THE PUZ ZLIN G BEAUTY OF NUMBERS

Math problems? Call 1 − 800

− (10x)2 −sin(xy)

2.36z

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.20/41

Page 76: THE PUZ ZLIN G BEAUTY OF NUMBERS

Math problems? Call 1 − 800 − (10x)2

−sin(xy)

2.36z

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.20/41

Page 77: THE PUZ ZLIN G BEAUTY OF NUMBERS

Math problems? Call 1 − 800 − (10x)2 −sin(xy)

2.36z

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.20/41

Page 78: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

× × ×× × × ×

× ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.21/41

Page 79: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 80: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 81: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 82: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 83: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 84: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 85: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 86: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 87: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 88: THE PUZ ZLIN G BEAUTY OF NUMBERS

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

×

×

×

×

× × ×

× ×

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.22/41

Page 89: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

A right hexagon is split into 24 triangles.

22 8 17

23 20 24 33

28 19 88 9 1

2 4 54 7

0 42 5

× × ×

× × ×× × × ×

× ×

19 different numbers are written in 19 nodes. Prove that at least

7 of 24 triangles have the following property: The numbers in its

vertices increase (from the least to the greatest) counterclockwise.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.23/41

Page 90: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 91: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 92: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 93: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 94: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 95: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 96: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We now note that

4=2+2 14=3+11 24=3+11 34=3+316=3+3 16=3+13 26=7+19 36=5+318=3+5 18=5+13 28=5+23 38=7+3110=3+7 20=7+13 30=7+23 40=3+3712=5+7 22=5+17 32=3+29 42=5+37

Goldbach’s Conjecture: Every even positive integer greater that 2

can be written as the sum of two primes.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.24/41

Page 97: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 98: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 99: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 100: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 101: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 102: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 103: THE PUZ ZLIN G BEAUTY OF NUMBERS

DEFINITION:

A prime number is a positive integer greater than 1 that is divisible

by no positive integers other than 1 and itself.

EXAMPLE: The integers 2, 3, 5, 7, 11, 13, 17, 19 are primes.

We also note that

220

+ 1 = 3 is a prime

221

+ 1 = 5 is a prime

222

+ 1 = 17 is a prime

223

+ 1 = 257 is a prime

224

+ 1 = 65537 is a prime

225

+ 1 = 4294967297 is composite!

In fact, one can check that 4294967297 = 641 · 6700417.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.25/41

Page 104: THE PUZ ZLIN G BEAUTY OF NUMBERS

TRUE OR NOT TRUE?

Numbers 8 and 9 are the only consecutive powers.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.26/41

Page 105: THE PUZ ZLIN G BEAUTY OF NUMBERS

Cathalan’s Conjecture:

Numbers 8 and 9 are the only consecutive powers.

TRUE (Michalesku, 2002).

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.27/41

Page 106: THE PUZ ZLIN G BEAUTY OF NUMBERS

Cathalan’s Conjecture:

Numbers 8 and 9 are the only consecutive powers.

TRUE (Michalesku, 2002).

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.27/41

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THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

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THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

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THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

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THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

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THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

Page 112: THE PUZ ZLIN G BEAUTY OF NUMBERS

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

Page 113: THE PUZ ZLIN G BEAUTY OF NUMBERS

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

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THE P U Z Z L I N G BEAUTY OF NUMBERS – p.28/41

Page 115: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM:

For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 116: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 117: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 118: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF:

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 119: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY):

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 120: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT):

Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 121: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 122: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 123: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 124: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 125: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 126: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.29/41

Page 127: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 128: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 129: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 130: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 131: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 132: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 133: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 134: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 135: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 136: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 137: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we havea1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

f(a1, a2, a3, . . . , an) =a1 + a2 + a3 + . . . + an

n− n

√a1a2a3 . . . an

f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

=

a1+a2

2+ a1+a2

2+a3+. . .+an

n− n

q

a1+a2

2

a1+a2

2a3 . . . an

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.30/41

Page 138: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.31/41

Page 139: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.31/41

Page 140: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some

x1, . . . , xn ∈ [A, B]. Suppose that f(x1, . . . , xn) attains its

minimal value on [A, B] at some a1, . . . , an ∈ [A, B] with

a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

(

a1+a2

2,a1+a2

2, a3, . . . , an,

)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.31/41

Page 141: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.32/41

Page 142: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

THEOREM:

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.32/41

Page 143: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

THEOREM (Extreme-Value Theorem):

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.32/41

Page 144: THE PUZ ZLIN G BEAUTY OF NUMBERS

THEOREM: For any a1, . . . , an ≥ 0 we have

a1 + . . . + an

n≥ n

√a1 . . . an

PROOF (ELEMENTARY, SHORT): Put

f(x1, . . . , xn) =x1 + . . . + xn

n− n

√x1 . . . xn

Assume to the contrary that f(x1, . . . , xn) < 0 for some x1, . . . , xn ∈ [A, B].

Suppose that f(x1, . . . , xn) attains its minimal value on [A, B] at some a1, . . . , an ∈[A, B] with a1 6= a2. This gives us a contradiction, since

f(a1, a2, a3, . . . , an)>f

a1+a2

2,

a1+a2

2, a3, . . . , an,

«

THEOREM (Extreme-Value Theorem): If f(x1, . . . , xn) is contin-

uous on a closed and bounded set R, then f has both an absolute

maximum and an absolute minimum on R.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.32/41

Page 145: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 146: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 147: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 148: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 149: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 150: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 151: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2 u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 152: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2 u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 153: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 154: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 155: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 156: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 157: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =

2 sin x cos x dx

=

sin x = u

d sin x = du

cos x dx = du

=

2u du

= u2 + C

= sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 158: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 159: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 160: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 161: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 162: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 163: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 164: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 165: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 166: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 167: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 168: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 169: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 170: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 171: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 172: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 173: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 174: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 175: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 176: THE PUZ ZLIN G BEAUTY OF NUMBERS

We have:∫

sin 2x dx =1

2

2 sin 2x dx

sin 2x dx =

2 sin x cos x dx

=

2x = u

d2x = du

2 dx = du

=

sin x = u

d sin x = du

cos x dx = du

=1

2

sin u du =

2u du

= −1

2cos u + C = u2 + C

= −1

2cos 2x + C = sin2 x + C

1. There is a mistake. Where???

2. −1

2cos 2x = sin2 x. Wrong!

3. −1

2cos 2x +

1

2= sin2 x. Correct.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.33/41

Page 177: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4= +∞

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 178: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4= +∞

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 179: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4= +∞

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 180: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4=

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 181: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4= + 4

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 182: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4= +

4

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 183: THE PUZ ZLIN G BEAUTY OF NUMBERS

limx→8+

1

x − 8= +∞

limx→4+

1

x − 4= +

4

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.34/41

Page 184: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 185: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 186: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 187: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 188: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 189: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 190: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 191: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 192: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 193: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 194: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 195: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 196: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 197: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 198: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 199: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 200: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 201: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 202: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 203: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 204: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 205: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 206: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 207: THE PUZ ZLIN G BEAUTY OF NUMBERS

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

1 = 1 7 = 1 + 2 + 4

2 = 2 8 = 8

3 = 1 + 2 9 = 1 + 8

4 = 4 10 = 2 + 8

5 = 1 + 4 11 = 1 + 2 + 8

6 = 2 + 4 12 = 4 + 8THE P U Z Z L I N G BEAUTY OF NUMBERS – p.35/41

Page 208: THE PUZ ZLIN G BEAUTY OF NUMBERS

1=1 16=16 31=1+2+4+8+162=2 17=1+16 32=323=1+2 18=2+16 33=1+324=4 19=1+2+16 34=2+325=1+4 20=4+16 35=1+2+326=2+4 21=1+4+16 36=4+327=1+2+4 22=2+4+16 37=1+4+328=8 23=1+2+4+16 38=2+4+329=1+8 24=8+16 39=1+2+4+3210=2+8 25=1+8+16 40=8+3211=1+2+8 26=2+8+16 41=1+8+3212=4+8 27=1+2+8+16 42=2+8+3213=1+4+8 28=4+8+16 43=1+2+8+3214=2+4+8 29=1+4+8+16 44=4+8+3215=1+2+4+8 30=2+4+8+16 45=1+4+8+32

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.36/41

Page 209: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 210: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 211: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 212: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a16 − 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 213: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a8 − 1)(a8 + 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 214: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a4 − 1)(a4 + 1)(a8 + 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 215: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a2 − 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 216: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a − 1)(a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 217: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a − 1)(a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 218: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)(a31 + a30 + a29 + . . . + a2 + a + 1)11111111

a32 − 1 ≡ (a − 1)(a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 219: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 220: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 221: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 222: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 223: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 224: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 225: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 226: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16+

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 227: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 1+ 1111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16+

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 228: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 1+ 1111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16+

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16+

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

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a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 1++ 1111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16+

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16+

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

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a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 1++ 1111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16+

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16+ + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16+

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

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a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

Page 232: THE PUZ ZLIN G BEAUTY OF NUMBERS

a32 − 1 ≡ (a − 1)a31 + a30 + a29 + . . . + a2 + a + 11111111111111111

a32 − 1 ≡ (a − 1)≡ (a + 1)(a2 + 1)(a4 + 1)(a8 + 1)(a16 + 1)

a32 − 1 ≡ (a − 1)≡ 1 + a + a2 + a1+2 + a4 + a1+4 + a2+4

a32 − 1 ≡ (a − 1) ≡ 1 + a1+2+4 + a8 + a1+8 + a2+8 + a1+2+8

(a − 1) ≡ 1 + a4+8 + a1+4+8 + a2+4+8 + a2+4+8+16

(a − 1) ≡ 1 + a16 + a1+16 + a2+16 + a1+2+16 + a4+16

(a − 1) ≡ 1 + a1+4+16 + a2+4+16 + a1+2+8+16 + a8+16

(a − 1) ≡ 1 + a1+4+8+16 + a2+8+16 + a1+8+16 + a4+8+16

(a − 1) ≡ 1 + a1+2+4+8 + a1+2+4+16 + a1+2+4+8+16

a2n−1 + a2n−2 + a2n−3 + . . . + a2 + a + 1

≡ (a + 1)(a2 + 1)(a4 + 1) . . . (a2n−1

+ 1)

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.37/41

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1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 234: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 235: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 236: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 237: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 238: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 239: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 240: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 241: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 242: THE PUZ ZLIN G BEAUTY OF NUMBERS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 243: THE PUZ ZLIN G BEAUTY OF NUMBERS

GENERATING FUNCTIONS

1

1 − a= 1 + a + a2 + a3 + . . . 1, 2, 22, . . . ⇒ N

= (1 + a)(1 + a2)(1 + a4) . . .

1

(1 − a)2= 1 + 2a + 3a2 + 4a4 + . . . x1 + x2 = N

= (1 + a + a2 + a3 + . . .)2

1

(1 − a)3= 1 + 3a + 6a2 + 10a4 + . . . x1 + x2 + x3 = N

= (1 + a + a2 + a3 + . . .)3

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.38/41

Page 244: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

Page 245: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

Page 246: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

Page 247: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

Page 248: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

Page 249: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

Page 250: THE PUZ ZLIN G BEAUTY OF NUMBERS

100 = 64 + 32 + 4

= 1 · 64 + 1 · 32 + 0 · 16 + 0 · 8 + 1 · 4 + 0 · 2 + 0 · 1

= (11001001)2

PROBLEM:

Consider the following weights:

1 2 4 8 16 32 64 128 etc.

Which weight can be weighed by them?

ANSWER:

Any, since any decimal number can be converted into the binarysystem.

THE P U Z Z L I N G BEAUTY OF NUMBERS – p.39/41

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