Mathcad - CAPE - 2007 - Math Unit 2 - Paper 01

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    CAPE 2007Pure Mathematics Unit 2 - Paper 01

    Section A - Module 1

    1 a( ) In the diagram below the curves y 2 e2 xx

    and y exx

    intersect

    at P (p, q)

    2 e2 x

    ex

    x

    1 0 1 2

    1

    1

    2

    Determine the values of p and q [5 marks]

    b( ) Solve 22 x 1

    622 x 1

    for x R [3 marks]

    a( ) 2 e 2 x e x2 e 2 x x 2e

    2 x1e

    x02

    e2 x

    1e

    x2 ex 02 ex x = ln 2

    y1

    eln 2.

    y1

    eln 2.

    y1

    2P ln 2.

    1

    2,.

    b( ) 2 x 1( ) ln 2. ln 6.2 x 1( ) ln 2. x1

    2

    ln 6.

    ln 2.1.x

    1

    2

    ln 6.

    ln 2.1. x = 0.792 (3 d.p)

    Alternatively: 2 22 x. 62 22 x.

    x1

    2

    lg 3.

    lg 2.

    lg

    lgx = 0.792 (3 dec places)

    1

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    2 a( ) The parametric equations of a curve are x4

    ttand y 2 t

    22t

    Find the gradient of the curve at the point (4, 4) [5 marks]

    b( ) Differentiate with respect to x y tan2

    3 x ln x3.x x [4 marks]

    a( )dy

    dx

    4 t

    4

    t2

    dy

    dx

    t

    t

    simplifies to t3

    x = 4 t = 1dy

    dx1

    1dy

    dx

    b( )dy

    dx2 tan. 3 x( ). 3 sec

    23 x( )..

    1

    x3

    3 x2

    3 sec2

    3 x( ). 3 x2

    x x

    x

    x

    dy

    dx6 tan. 3 x( ). sec

    2. 3 x( )3

    x3 x( )

    xx x

    x

    3 a( ) Express5

    3 x( ) 2 x( ).in the form

    P

    3 x

    Q

    2 xwhere P and Q are

    constants

    [3 marks]

    b( ) Hence find x5

    3 x( ) 2 x( ).d [3 marks]

    a( ) 5 P 2 x( ). Q 3 x( ).5 P x Q x P 1 Q 1

    5

    3 x( ) 2 x( ).

    1

    3 x

    1

    2 x

    5

    3 x( ) 2 x( ). x x

    b( ) x1

    3 xd

    1

    2 xln 3 x( ). ln 2 x( ). ln K.ln 2 x( ). Kx x

    I ln k 3 x

    2 x.. k

    x

    x

    2

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    4 Obtain the following

    a( ) xx 2 x 5( )4. d by substituting u = 2x - 5 [5 marks]

    b( ) xx sec2

    x. d using integration by parts [4 marks]

    a( )1

    2du dx

    1

    2du dx x

    1

    2u 5( )u

    I u1

    2

    u 5( ) u4 1

    2

    . du I1

    4

    uu5

    5 u4

    d. u

    I1

    4

    u6

    6u

    5. Ku

    6

    6u

    5K

    uu I

    u5

    24u 6( ) Ku 6( ) K

    uu I

    2 x 5( )5

    2 x 1( )

    24K

    24K

    x x

    b( ) I x tan. x. xtan x. dx x x I x tan. x. ln cos x.. Kln cos x.. Kx x x

    5 The cost $c of manufacturing x items may be modelled by the differential equation

    dc

    dx2 c 10 x

    dc

    dx2 c x

    By using a suitable integrating factor solve the differential equation given that there is a costof $100 when no items are produced

    [8 marks]

    I e

    x2 d x

    I e2 xx

    e2 x dc

    dx. 2 e

    2 xc e

    2 x10 x.e

    2 x dc

    dx. 2 e

    2 xc

    xx

    xd

    dxc e

    2 x. d xe2 x

    10 xdxd

    dxc e

    2 x. d x

    c e2 x.

    1

    2e

    2 x10 x x

    1

    2e

    2 x10( ) dc e

    2 x. x x x

    3

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    c e2 x.

    1

    2e

    2 x10 x

    5

    2e

    2 xK

    5

    2e

    2 xK

    xx

    xx = 0 c = 100

    100

    1

    2 0( )

    5

    2 1( ) K

    5

    2 1( ) K K

    205

    2 c 5 x

    5

    2

    205

    2 e2 xx x

    Section B - Module 2

    6 A sequence {un} is defined by un 1 un 2n

    un 1

    un

    nn 1

    a( ) Prove that un 2

    2 un

    unn

    [4 marks]

    b( ) If u1 2 find u3 and u5 [4 marks]

    a( ) un 1

    2n

    un

    n

    nn

    un 2

    2n 1

    un 1

    n

    nn

    un 2

    22

    n

    un 1

    .n

    nn

    2n

    un 1

    un

    2n

    un 1

    nu

    n 22 u

    n.

    nn

    b( ) u1

    2 u3

    2 2( ). yields 4 u3

    2 u1

    .

    u5

    2 4( ). yields 8 u5

    2 u3

    .

    7 The sum of the first and third terms of a GP is 50 and the sum of the second and fourth termsis 150. For this GP find

    a( ) the common ratio [4 marks]

    b( ) the first term [2 marks]

    c( ) the sum of the first five terms [2 marks]

    a( ) a 1 r2. 50a 1 r2. ar 1 r

    2. 150ar 1 r2. r = 3

    b( ) a = 5 c( ) S5

    5 35

    1.

    3 1yields 605

    4

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    8 Find the term independent of x in the expansion of 2 x2 5

    x3

    10

    [7 marks]

    10( ) 9( ) 8( ) 7( )

    242( )

    65( )

    4yields 8400000

    9 a( ) Use the fact that nC

    k

    n !

    k! n k( ) !.Ck

    n

    k n kkto express in terms of factorials

    i( ) the coefficient u of xn

    in the expansion of 1 x( )2 n

    [2 marks]

    ii( ) the coefficient v of xn

    in the expansion of 1 x( )2 n 1

    [3 marks]

    b( ) Hence show that u = 2v [4 marks]

    a( ) i( )2 n( ) !

    n ! 2 n n( ) !.x

    n 2 n( ) !

    n !( ) n !( )x

    n.2 n( ) !

    n ! 2 n n( ) !.x

    n n

    n nx

    nu

    2 n( ) !

    n !( ) n !( ).

    n

    n n

    ii( )2 n 1( ) !

    n ! 2 n 1 n( ) !.x

    n 2 n 1( ) !

    n ! n 1( ) !.x

    n2 n 1( ) !

    n ! 2 n 1 n( ) !.x

    n n

    n nx

    nv

    2 n 1( ) !

    n ! n 1( ) !.

    n

    n n

    iii( )2 n( ) 2 n 1( ) !

    n !( ) n. n 1( ) !.u

    2 n( ) 2 n 1( ) !

    n !( ) n. n 1( ) !.u

    2 2 n 1( ) !.

    n ! n 1( ) !.

    n

    n nu 2 vv

    10 a( ) Given that f r( ).2 r 1

    r 1( ) r 2( ).f r( ).

    r

    r rprove that

    f r( ). f r 1( ).2 r 3( ).

    r r 1( ). r 2( ).f r( ). f r 1( ).

    r

    r r r[4 marks]

    b( ) Hence find

    3

    n

    r

    r 3

    r r 1( ). r 2( ).=

    [4 marks]

    a( )2 r 1

    r 1( ) r 2( ).

    2 r 3

    r r 1( ).

    r 2 r 1( ). r 2( ) 2 r 3( )

    r r 1( ). r 2( ).

    2 r 1

    r 1( ) r 2( ).

    2 r 3

    r r 1( ).

    r r r r

    r r r

    f r( ). f r 1( ).2 r 3( ).

    r r 1( ). r 2( ).f r( ). f r 1( ).

    r

    r r r

    5

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    b( )

    2 Sn

    7

    2

    9

    6

    9

    6

    11

    12...

    2 n 1

    n 1( ) n 2( ).

    2 n 3

    n n 1( )....

    Sn

    1

    2

    7

    2

    2 n 3

    n n 1( ).

    n

    n nnS

    n

    7 n2

    11 n 6

    4 n n 1( ).

    n n

    n nn

    Section C - Module 3

    11 a( ) Determine the number of ways in which the letters of the word S T A T I S T I C S

    may be arranged so that the vowels are placed together

    [3 marks]

    b( ) A team of five is chosen at random from 4 boys and 6 girls. Calculate the numberof ways that this team can be chosen to include at least 3 girls

    [5 marks]

    a( ) vowels are A I I considered as one item

    1 7( ) ! 3 !

    3 ! 3 !. 2 !.3360 ways

    1 7( ) ! 3 !

    3 ! 3 !. 2 !.ways

    b( )

    (3 girls from 6 and 2 boys from 4) or (4 girls from 6 and 1 boy from 4)or (5 girls from 6 and no boys)

    6C

    34

    C2

    . 6C

    44

    C1

    . 6C

    54

    C0

    .

    120( ) 60( ) 6( ) 186120( ) 60( ) 6( )

    6

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    12 Two unbiased dice each with six faces are tossed randomly one after another

    a( ) Determine the set of possible outcomes [2 marks]

    b( ) Find the probability that

    i( ) the product of the numbers on the two dice is a multiple of 5 [2 marks]

    ii( ) the second die shows the number 2 [1 mark]

    iii( ) the product of the numbers on the two dice is a multiple of 5 or the seconddie shows the number 2

    [2 marks]

    a( )

    {(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6),(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6),(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6), (6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)}

    b( ) i( )11

    36ii( )

    1

    6iii( )

    11

    36

    6

    36

    1

    36

    4

    9

    11

    36

    6

    36

    1

    36

    13 The matrices X and Y are given by X =

    4

    5

    7

    2

    6

    9

    1

    8

    3

    and Y =

    1

    5

    4

    6

    2

    6

    Calculate

    a( ) the determinant of X [4 marks]

    b( ) YT

    X [3 mark]

    a( ) X 4 18( ) 72( )( ). 2 15( ) 56( )( ). 45( ) 42( )X yields 365

    4

    5

    7

    2

    6

    9

    1

    8

    3

    yields 365

    b( ) 1

    6

    5

    2

    4

    6

    4

    5

    7

    2

    6

    9

    1

    8

    3

    . yields7

    56

    68

    78

    29

    4

    7

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    14 Y and X are 3 x 1 matrices and are related by the equation Y = AX where

    A

    1

    7

    3

    0

    5

    2

    3

    0

    1

    is a non-singular matrix

    a( ) Find A1

    [6 marks]

    b( ) X, when Y =

    10

    12

    8

    [3 marks]

    a( )

    A1

    1

    7

    3

    0

    5

    2

    3

    0

    1

    1

    A1

    yields

    5

    2

    7

    2

    1

    2

    3

    4

    1

    15

    2

    21

    2

    5

    2

    b( ) 10

    12

    8

    1

    7

    3

    0

    5

    2

    3

    0

    1

    X.

    10

    12

    8

    X

    X

    5

    2

    7

    2

    1

    2

    3

    4

    1

    15

    2

    21

    2

    5

    2

    10

    12

    8

    . yields

    1

    1

    3

    8

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    15 Air is pumped into a spherical balloon of radius r cm at the rate of 275 metres cube persecond. When r = 10 calculate the rate of increase of

    a( ) the radius r [5 marks]

    b( ) the surface area S [4 marks]

    [The volume V and surface area S of a sphere of radius r are given by

    V4 r

    3

    3

    rand S 4 r

    2r respectively]

    a( )dr

    dt

    dr

    dV

    dV

    dt.

    dr

    dt

    dr

    dV

    dV dr

    dt

    1

    4 r2

    275( )dr

    dt r

    dr

    dt10

    275

    4 10( )2

    dr

    dtyields

    11

    16 .( )cm

    b( ) dSdt

    dSdr

    drdt

    .dSdt

    dSdr

    dr dSdt

    8 r 1116

    .dSdt

    r

    dS

    dt10

    8 . 10( ).11

    16

    dS

    dtyields 55 cm

    2

    9