Page 70 - ACE YR IGCSE A TOP APPR' TO ADD MATH
P. 70

p(1) = 9                                          Kinematics
                      4(1)  – 6(1)  + c(1) = 9
                               2
                         3
                                    c = 11                           1.  (a)  When t = 3, v = 0.
                      p(x) = 4x  – 6x  + 11x                              3a(3)  – 2b(3) = 0
                                  2
                             3
                                                                               2
                                                            [4]               27a – 6b  = 0 …… (1)
                    26.  y = –x  + 16x – 48                               s =   3at  – 2bt dt
                           2
                                                                                 2
                      dy  = –2x + 16
                      dx                                                    =  3at 3  –  2bt 2  + c
                                                                                    2
                                                                              3
                        –2x + 16 = 0                                        = at  – bt  + c
                                                                               3
                                                                                   2
                            x = 8
                                                                          When t = 0, s = 0, so c = 0.
                      When x = 8,                                         When t = 3, s = –1
                            2
                      y = –(8)  + 16(8) – 48                               a(3)  – b(3)   = –1
                                                                               3
                                                                                     2
 =  1                   = 16                                                  27a – 9b  = –1 …… (2)
 2                    S(8, 16)
                                                                          Equation (1) – Equation (2)
 = √3                 When y = 0,                                         3b = 1
                        2
                      –x  + 16x – 48 = 0
 = √(7)  –            x = 4  or  x = 12                                    b =  1 27Rights Reserved.
 2
                                                                               3
                                                                                 1
                      P(4, 0) and Q(12, 0).                               27a – 6 1 2   = 0
 2
 2
 =  1 8  + 3          Equation of line PQ,                                       3 a =   2
 2
 1                    m =   16 – 0   = –  4                                          27                      [5]
 = 2  2                   0 – 12   3
                                                                                2
                                                                                        1
                        Penerbitan Pelangi Sdn Bhd. All
 =                         4                                           (b)  V = 3 1 2 t  – 2 1 2 t
                                                                                   2
   2                  y = –  x + 16                                                     3
 (b)                       3                                                  2 2  2
                                      2
                                                                                   3
                                                                              9
 1                        –  4 x + 16  = –x  + 16x – 48                     =  t  –  t
                            3
                                                                               4
 ==                        –4x + 48  = –3x  + 48x – 144                    dv  =  t –  2
                                       2
                      3x  – 52x + 192  = 0                                 dt  9    3
                        2
                                 x  =  16   or  x = 12                    When  dv  = 0,
                                     3                                     4   2 dt
                      When x =  16 ,                                       9 t =  3
                               3                                               3
                           4 16                                               t =   s
                      y = –   1 2  + 16                                        2
                           3 3                                                                               [3]
                        =  80
                          9                                          2.  (a)  When t = 0,
                      T  1 16  ,   80 2	                                    a = 4 – 2(0)
                                                                            = 4 m s
                                                                                 –2
                             9
                         3
                       16                                                                                    [1]
                       3
                         –x  + 16x – 48 dx
                           2
                       8                 8                             (b)  v =   4 – 2t dt
                        3
                      =  –  x 3 3   +   16x 2   – 48x] 4 16 3               = 4t –  2t 2  + c
                                2
                                                                                  2
                                                                                 2
                        1
                      =  –  128 2 1  6400 2                                 = 4t – t  + c
                               –  –
                           3
                                   81
                                                                          When t = 0, v = 16.
                                                                                2
                      =  2944                                               4(0) – 0  + c = 16
                         81                                                        c = 16
                                             2
                                                                                 2
                      Area = (8 × 16) – 3 1 16 +  80 16  1  2944 2           v = 4t – t  + 16

                                           9
                                               3
                                                                             dv
                                          2      4 –   81                    dt   = 0
                          =  2048                                          4 – 2t  = 0
                             81                                              2t  = 4
                          = 25.28 unit                                        t  = 2
                                    2
                                                            [10]
                                                                          Maximum velocity = 4(2) – 2  + 16
                                                                                                  2
                                                                                          = 20 m s
                                                                                                 –2
                                                                                                             [5]
                         Cambridge IGCSE
                                          TM
                  210     Ace Your Additional Mathematics
         Answers Add Math.indd   210                                                                             14/03/2022   12:29 PM
   65   66   67   68   69   70   71   72   73