Mathematics P2 Memo March 2010 Eng

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    MARKS: 150

    This memorandum consists of 14 pages.

    MATHEMATICS P2

    FEBRUARY/MARCH 2010

    MEMORANDUM

    NATIONALSENIOR CERTIFICATE

    GRADE 12

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    QUESTION 1

    1.1 Range = 26 4 =22 maximum and minimumvalues

    answer ANSWER ONLY: Full Marks(2)

    1.2 Mean

    =12

    71417232625221913854 +++++++++++

    =12

    183

    method

    183answer

    = 15,25 (3)

    1.3 Standard deviation = 7,6 (7,59522..) answer (2)

    1.4.1Increase in mean =

    ( ) ( )12

    1953 +

    C2= per month. answer (2)

    1.4.2 The maximum value increases by 1C and theminimum value increases by 5C. This implies thatthe range of the range of the data will now decrease.This will result in the standard deviation gettingsmaller. (new SD = 6,27..)

    decrease in range

    decrease in standard deviation(2)

    [11]

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    QUESTION 2

    2.1.1Survey of training and goals scored

    0

    2

    4

    6

    8

    10

    12

    1416

    0 5 10 15 20 25

    Hours of training

    N u m

    b e r o

    f g o a

    l s s c o r e

    d

    plotting the points

    All 9 pointcorrect 3 marks5 or 7 pointscorrect 2 marks1 or 2 pointscorrect 1 mark 0 points correct 0 marks

    (3)

    2.1.2 A(indicated on the graph) answer (1)

    2.1.3 8 Goals answer (2)

    2.2 Let the mean time for all 560 learners be x.Then the mean time for the learners living in neighbourhood C is also

    x.

    560

    )200()32225()24135( x x

    ++=

    29

    10440360

    20072003240560

    ==

    ++=

    x

    x

    x x

    equal meantimes

    mean number

    simplification

    answer (4)

    [10]

    A

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    4 DoE/Feb.

    QUESTION 3

    0 10 20 30 40 50 60

    1511

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    QUESTION 4

    4.121

    4002 =

    =PQm

    substitution(1)

    4.2A:

    ++2

    02;

    2

    40

    A (2 ; 1) x-coordinate y-coordinate

    (2)4.3 1. =PQ AB mm

    1)2/1.( = ABm , 2= ABmEquation of AB is y = 2 x + c 1 = 2(2) + cc = 3

    Equation of AB is y = 2 x 3 .

    OR1. =PQ AB mm

    1)2/1.( = ABm , 2= ABm

    32

    421

    )2(21

    ===

    x y

    x y

    x y

    1. =PQ AB mm 2= ABmequation of AB

    y = 2 x 3 c = 3

    (5)

    1. =PQ AB mm 2= ABm

    gradient of ABsubstitution into

    formulaequation of AB

    (5)4.4 B is the point (0 ; 3)

    5

    )03(4)-(0BQ 22

    =

    +=

    coordinates of Bsubstitutionanswer

    (3)4.5

    5

    )23(0)-(0BP 22

    =+=

    BP = BQBPQ is isosceles.ORBP = 2 + 3

    = 5BP = BQBPQ is isosceles

    BP = 5BP = BQ

    (2)

    BP = 5BP = BQ

    (2)4.6 If PBQR is a rhombus then A is the midpoint of BR.

    Let the coordinates of R be ( x ; y)

    4

    22

    0

    =

    =+

    x

    xand

    5

    12

    3

    =

    =

    y

    y

    R(4 ; 5)

    OR RQ || PB so 4= R x

    RQ = PB = 5, so 5= R y R(4 ; 5)

    A is the midpoint of BR

    x coordinate y coordinate

    (3)

    RQ || PB x coordinate

    y coordinate(3)

    [16]

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    QUESTION 5

    x

    y

    P(5 ; 4)

    45

    BC

    D

    A

    O

    5.1AB is defined as 0535 = x y which can be written as 1

    53 += x y

    53= ABm

    Let be the inclination of AB.

    53tan =

    = 96.30 .

    Let be the inclination of CD = 45 + 30,96

    = 75,96

    Gradient of CD = tan 75,96 = 4.

    OR

    4

    tan

    4

    153

    1

    153

    45tan.tan145tantan

    )45tan(tan

    ===

    +=

    +=

    +=

    CD

    CD

    m

    m

    53= ABm

    53

    tan =

    = 96.30

    = 75,96

    gradient of CD(5)

    expansiontan 45 = 1tan =

    53

    substitutionanswer

    (5)

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    5.2 Equation of CD is y = 4 x + c 4 = 4(5) + cc = 16

    Equation of CD is y = 4 x 16 .

    OR

    164

    2044

    )5(44

    ===

    x y

    x y

    x y

    y- interceptequation of CD

    (2)

    substitutionequation of CD

    (2)[7]

    QUESTION 6

    6.1

    58)2()4(3841644168

    03848

    22

    22

    22

    =+++++=+++++

    =+++

    y x y y x x

    y x y x

    Centre is (4 ; 2) and the radius is 58

    completing thesquare (both or one)

    factor formcentreradius

    (4)6.2 Centre of second circle is (4 ; 6)

    Distance between centres is 31,11128)26()44( 2 ==+++ centredistance

    (2)6.3 Sum of radii = 71,122658 =+

    Distance between centres is 11,31.

    sum of the radii > distance between the centres

    the circles must overlap and hence the circles must intersect.

    sum of radii

    conclusion(3)

    6.4 Equation of second circle:( )

    026128

    263612168

    26)6(4

    22

    22

    22

    =++=+++

    =+

    y y x x

    y y x x

    y x

    Let ( x ; y) be either of the two points on intersection.Then

    026128

    0384822

    22

    =++=+++

    y x y x

    y x y x

    Subtract 0641616 =+ x y

    4+= x y Both points of intersection lie on this line. y = x + 4 is the equation of the common chord.

    OR

    equation of circle inform = 0

    statement two points of intersection

    subtracting

    simplification(4)

    and

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    Check that the line y = x + 4 cuts the two circles at the same points:

    ( )

    0)1)(3(

    032

    0642

    2644168

    26)2(4

    2

    2

    22

    22

    =+==

    =++++=+

    x x

    x x

    x x

    x x x x

    x x

    x = 3 or x = 1

    1or 3032

    0642

    0384168816

    038)4(48)4(

    03848

    2

    2

    22

    22

    22

    ===

    ==++++

    =+++=+++

    x x x x

    x x

    x x x x x

    x x x x

    y x y x

    substitution

    answer

    substitution

    answer (4)

    [13] QUESTION 7

    7.1.1 )2;5(/ P answer (1)

    7.1.2 )2;5(/P x coordinate y coordinate

    (2)7.2.1

    )7;6()12;14(:

    )9;5()10;18(:

    )8;4()8;16(:

    )9;3()6;18(:

    )2;2()4;14(:

    E E

    L L

    H H

    U U

    K K

    So halve and interchange or interchange and halve.

    Reflection across y = x followed by contraction by

    2

    1

    OR

    Contraction by21

    followed by reflection across y = x.

    reflectedthe line y = x enlarged

    scale factor of 21

    (4)

    7.2.2)4;8()8;16(

    21/ == H

    OR )16;8(/ H

    (8 ; 4)

    (8 ; 16)(2)

    7.2.3Area KUHLE : Area =////////// ELHUK

    2

    12

    = 4 : 1 answer

    (2)[11]

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    QUESTION 8

    8.1 For anti-clockwise rotation:

    2323

    23

    221

    3

    60sin2)60cos(3

    120sin2120cos3

    sincos/

    =

    =

    =

    == y x x

    2233

    212

    233

    )60cos(260sin3

    120cos2120sin3

    cossin/

    =

    +

    =

    +=+=

    += y x y

    2

    233;

    2323/P

    formula

    simplificationsubstitution

    answer

    simplification

    answer

    (6)8.2

    =

    23

    21

    2 y x

    y x 34 = equation 1

    +

    =

    21

    23

    0 y x

    y x += 30 x y 3= equation 2

    Substitute equation 2 into equation 1

    32

    2

    24

    34

    334

    ===

    +==

    y

    x

    x

    x x

    x x

    Q 32;2

    y x 34 =

    x y 3=

    x-coordinate y-coordinate

    (4)[10]

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    QUESTION 9

    9.1.153

    sin = and54

    cos =

    57

    cossin =+

    correct quadrantand values.

    53

    sin =

    54

    cos =

    answer (4)

    9.1.2

    724

    2592516

    54

    53

    2

    sincoscossin2

    2cos2sin

    2tan 22

    =

    =

    ==

    OR

    724

    43

    1

    432

    tan1tan2

    2tan

    2

    2

    =

    =

    =

    4

    53

    2cos2sin

    sin 2 = 2sin .cos cos 2 = cos 2

    sin2 substitution

    answer (5)

    expansion

    substitution

    answer (5)

    9.2.1

    x

    x x x

    x

    x x x x

    x x x x

    cos1

    sin1

    cossin

    )(cos

    )sin)(sin())(tan(cos

    )90cos().180sin(tan).360cos(

    22

    2

    2

    2

    =

    =

    =

    +

    cos x sin x

    sin x

    x x

    2

    2

    cossin

    answer (5)

    9.2.2 x = 30

    3

    2

    23

    130cos

    1 ==

    x = 30

    answer (2)

    [16]

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    QUESTION 10

    10.1.1

    q p +=

    +=+=

    12sin36cos12cos36sin

    )1236sin(48sin

    writing 48 in terms of

    36 and 12 expansionanswer

    (3)

    10.1.2

    q p ==

    =12sin36cos12cos36sin

    )1236sin(24sin

    OR

    q p ==

    =12sin36cos12cos36sin

    )1236sin(24sin

    writing 24 in terms of 36 and 12

    expansionq p =24sin

    (3)

    writing 24 in terms of 36 and 12 expansion

    q p =24sin (3)

    10.1.3

    )(224cos

    24cos)(2

    24cos24sin248sin

    q pq p

    q pq p

    +=

    =+=

    OR

    ( )( )

    ++=

    +=+=

    =

    2

    2

    2

    1121

    48sin1121

    248cos1

    24cos

    124cos248cos

    q p

    OR

    = 24sin124cos 22 22 )(124cos q p =

    2)(124cos q p =

    124cos248cos 2 =q p +=48sin

    answer (3)

    124cos248cos 2 =q p =24sin

    answer (3)

    = 24sin124cos 22q p =24sin

    answer (3)

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    10.2

    ( )

    23

    )20cos20(sin23

    20sin21

    20cos23

    20sin

    20sin41

    20sin20cos23

    20cos43

    20sin41

    20sin20cos23

    20cos43

    20sin

    20sin21

    20cos23

    20sin21

    20cos23

    20sin

    )20sin60cos20cos60(sin20sin60cos20cos60sin20sin

    ))2060(sin())2060(sin(20sin

    80sin40sin20sin

    22

    222

    2

    2222

    22

    2

    222

    222

    222

    =

    +=

    ++=

    ++

    +++=

    ++

    +=

    +++=+++=

    ++

    OR

    Use2

    2cos1sin 2

    =

    ( ){ }

    ( ){ }

    ( ){ }

    23

    023

    20cos20cos21

    221

    23

    20cos20cos60cos221

    23

    160cos40sin60sin40cos.60cos40sin60sin40cos.60cos21

    23

    160cos80cos40cos21

    23

    =

    =

    =

    =

    +++=

    ++=

    LHS

    40= 60 -20

    80= 60 +20

    expansions

    substitution

    simplification

    factorisation

    (7)

    40= 60 20

    80= 60 +20

    expansionof cos 40

    expansionof cos 60

    simplification

    simplification

    answer for bracket

    (7)

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    10.3.1

    x

    x x x

    x x

    x x

    x x x x

    x x x x

    cos1

    )cos1()cos1)(cos1(

    cos1cos1cos1

    sin

    cos1)cos(sinsin

    cos1cossinsin

    2

    2

    222

    224

    =+

    +=

    +=

    +=

    ++=

    ++

    factorisation

    1cossin 22 =+ x x

    identity

    factorisation

    (4)

    10.3.2

    Z k k x

    x

    x

    +===+

    ;360.180

    1cos

    0cos1

    Undefined for Z k k x += ;360.180 .

    0cos1 =+ x

    180 + k.360 (2)[22]

    QUESTION 11

    11.1

    0)sin21(sin

    0sin2sin

    sin21sin1

    2cossin1

    2

    2

    =+=+

    =+=+

    x x

    x x

    x x

    x x

    0sin = x or `21

    sin = x

    180.k x = or 360.30 k x += Z k 360.210 k x +=

    { } 036;330;210;180 x

    OR

    0)sin21(sin

    0sin2sin

    sinsin1sin1

    sincossin1

    2cossin1

    2

    22

    22

    =+=+

    =+=+

    =+

    x x

    x x

    x x x

    x x x

    x x

    0sin = x or `21

    sin = x

    180.k x = or 360.30 k x += Z k 360.210 k x +=

    { } 036;330;210;180 x

    expansion

    factorisation

    equations

    180.k x =solution for

    `21

    sin = x

    answers(7)

    expansion

    factorisation

    equations

    180.k x =solution for

    `2

    1sin = x

    answers(7)

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    11.2

    45 90 135 180 225 270 315 360

    -3

    -2

    -1

    1

    2

    3

    x

    y

    f

    g

    1+sin x max and min

    valuesshape

    cos2 xamplitudeintercepts

    (4)

    11.3 210180 x or 360330 x answer (3)

    [14]QUESTION 12

    12.1

    cos)sin(sin

    DE

    cosDF

    DEDE

    DFcos

    )sin(sin

    DF

    DFBC but

    )sin(sin

    BC

    sin)sin(BC

    sinBC

    )(180sin[

    +=

    =

    =

    +=

    =

    +=

    =+

    =+

    b

    b

    b

    b

    b

    sine rule

    )(180 +=C B A

    BC =

    BC = DF

    manipulation

    DE =

    (6)

    12.2 substitutionnumerator

    m1559,50 27cos.79sin

    43sin2000DE

    =

    =

    substitutiondenominator

    answer (3)

    [9]

    150TOTAL: