4.2 the wrapping function

19
Chapter 4.2 The Wrapping Function 1

Transcript of 4.2 the wrapping function

Chapter 4.2 The Wrapping Function

1

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5

1

0

2

1

2

2

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5

0

1

2

12

3

3

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5

1

0

2

12

3

4

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5

Each real number corresponds

to a length of an arc whose initial

point is 1,0 .

In counterclockwise direction,

the arc is positive.

In clockwise direction, the arc

is negative.

0

2

12

3

1

5

Wrapping Function

The is a function from

the set of real numbers to the set of all points

on the unit circle with center at the origin

such that

,

where , is the terminal p

wrapping fu

oint of the

n

arc

with leng

ction P

P t x y

x y

th and whose initial point is 1,0 .t

6

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5

,P t x y

t

,x y

7

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5Example 4.2.1

Evaluate the following.

1. 0,12

2. 2 1,0

3. 0 1,0

4. 1,0

P

P

P

P

2

2

3

2

8

-5 -4 -3 -2 -1 1 2 3 4 5

-5

-4

-3

-2

-1

1

2

3

4

5

5. 0, 12

6. 1,0

P

P

2

2

3

2

9

Special Arc Lengths

2

32

2

43

4

54

74

2 2,

4 2 2P

3 2 2,

4 2 2P

5 2 2,

4 2 2P

7 2 2,

4 2 2P

10

Special Arc Lengths

2

32

3

43

53

1 3,

3 2 2P

2 1 3,

3 2 2P

4 1 3,

3 2 2P

5 1 3,

3 2 2P

11

Special Arc Lengths

2

32

3

43

53

6

2

56

76

116

32

12

Special Arc Lengths

3 1,

6 2 2P

5 3 1,

6 2 2P

7 3 1,

6 2 2P

11 3 1,

6 2 2P

65

6

76

116

13

Challenge!

Evaluate the following.

5 2 2 2 1 31. , 5. ,

4 2 2 3 2 2

11 3 1 11 3 12. , 6. ,

6 2 2 6 2 2

1 3 1 33. , 7. ,

3 2 2 3 2 2

34.

4

P P

P P

P P

P

2 2 7 3 1, 8. ,

2 2 6 2 2P

14

Coterminal Arcs

Two arcs with the same terminal p

c

o

o

in

te

ts

ar rmine called al a rcs.

15

4 7

4 9

4

7 9, , and are coterminal arcs.

4 4 4

16

Coterminal Arcs

Coterminal arcs have equal wrapping

function values.

17

Example 4.2.2

Evaluate the following.

1. 3 1,0

2. 6 0 1,0

7 1 33. ,

3 3 2 2

101 5 2 24. ,

4 4 2 2

23 11 3 15. ,

6 6 2 2

P P

P P

P P

P P

P P

18

End of Chapter 4.2

19