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Mathematics Term 1  STPM  Answers
                 11.  U = 6r – 1; 9n  + 2n                      2.  (a)  1 –   x +   3   x  –   5   x ; |x| , 2
                                                                       1
                             2
                                                                                    3
                                                                              2

                   r
                                                                                 128
                                                                            4
                 12.   1 + 2r 2  ,   n(n + 2)                          4 2  32  40       1
                  r (r + 1)  (n + 1) 2                           (b)  1 –   x –   x  –   81  x ; |x| ,   2
                   2

                                                                                   3
                                                                              2
                                                                            9
                                                                       3
                 13.  A = 1, B = –3, C = 2                           1  1   1    1
                                                                                    3
                                                                 (c)   2   –   x +   x  –  16  x ; |x| , 2
                                                                               2

                                                                        4
                                                                            8
               Exercise 2.6                                      (d)  1 –   x +   x  –   5   x ; |x| , 1
                                                                            3
                                                                       1
                                                                                   3
                                                                              2

                 1.  (a)  120   (b)  40 320   (c)  3 628 800           2 1  8 5  16
                                                                                 3
                                                                                   3
                                                                              2

                  (d)  336     (e)  720      (f)  4896           (e)  1 –   x –   x  +   16  x ; |x| , 1
                                                                       2
                                                                            8
                  (g)  285     (h)  8008     (i)  1260           (f)  –1 + 2x – 2x  + 2x ;  |x| , 1

                                                                                 3
                                                                             2
                  (j)  252                                                 33  2  81  3     1
                 2.  (a)   10!  (b)  12!     (c)  22!            (g)  2 + 4x +   4   x  +   4   x ; |x| ,   3
                     7!           10!           19!              (h)  –   +   x –   13  x  +   51  x ; |x| ,   1
                                                                         3
                                                                      1
                                                                                2

                                                                                     3
                  (d)   18! 2!  (e)  21! 5!  (f)  n!                  2  4    8    16      2
                     15! 5!       18! 8!        (n – 3)!         (i)  1 – x + x ; –   (1 +  5 ) , x ,   ( 5 – 1)
                                                                                          1
                                                                             1
                                                                           3
                  (g)   (n + 2)!  (h)  (2n + 5)!  (i)  n!                    2            2
                     (n – 2)!     (2n + 2)!     (n – 1)! 3!     3.  1.1255
                  (j)   (n – 5)! 2!                             4.  30.43168
                     (n – 9)! 5!                                5.  1 + 30x + 420x  + 3 640x ; 1.03042
                                                                            2
                                                                                  3
                 3.  (a)  11(9!)      (b)  15(7!)                    2  3  4  5  6
                  (c)  291(7!)         (d)  (n + 2)n!           6.  1 – x  +   x  –   x
                                                                            2
                                                                        2
                                                                        1
                  (e)  (n + n – 1)(n – 1)!    (f)  n(n  + n + 2)n!    7.  1 –  x –   x  –   1   x ; 0.9487

                      2
                                                                    1
                                           2
                                                                                3
                                                                           2
                  (g)  (n + 1) (n – 1)!       (h)   31(7!)          2   8    16
                          2
                                         30(3! 2!)              8.  1.732
                  (i)   263(7!)       (j)  (n – 1)!   (nr + n + 1)    9.  3.1623 (5 sig.fig.)
                     210(3! 2!)          (r + 1)!                 1  1   3    1    5
                                                                                3
                                                                                     4
                                                                            2
                 4.  (a)  70   (b)  120   (c)  1140   (d)  1    10.   4   +  x +  16 x  +  x  +  64 x ; 0.309
                                                                              8
                                                                     4
                                                                            1
                                                                       1
                  (e)  200   (f)  560   (g)   15  (h)  26       11.  1 + x –   x  +   x ; 2.236
                                                                              3
                                                                         2
                                                                       2
                                                   45
                                         4
                                                                            2
                  (i)  6188   (j)  84                           12.  1 – 7x + 28x  – 112x ; |x| ,   1
                                                                          2
                                                                                3

                                                                                     4
                                                                                4
                                                                          3
               Exercise 2.7                                     13.  1 – 5x + 30x  – 15x ; 0.950 030
                          3
                                    3
                      4
                              2 2
                 1.  (a)  p  + 4p q + 6p q  + 4pq  + q 4      STPM PRACTICE 2
                                                     2
                                                      5
                                                4
                          6
                                         3
                      7
                                              3
                                       4
                  (b)  m  – 7m n + 21m n  – 35m n  + 35m n  – 21m n  +      th
                                 5
                                  2
                     7mn  – n 7                                 1.  n(n – 1); 15
                       6
                                                                          1
                                                                       1
                  (c)  64 + 192k  + 240k  + 160k + 60k  + 12k  + k 12    2.  (a)  3, 4  , 4  , 4 +   1  , n . 1
                            2
                                       6
                                                10
                                 4
                                           8
                                                                          6
                                                                       2
                                                                               n(n – 1)
                  (d)  32a  – 80a b + 80a b  – 40a b  + 10ab  – b 5  (b)  2, 4, 18, n(n!), n . 1
                       5
                            4
                                  3 2
                                       2 3
                                              4

                            3
                  (e)  x  + 3x +   +   1
                      3
                            x  x 3                              3.  (a)  250         (b)  510

                  (f)  y  – 4y  + 7y  – 7y  +  35  –   7 2  +   7 4  –   1  6  +   1  (c)  n(n + 1)         (d)  (n + 1)! – 1
                      8
                          6
                              4
                                 2
                                    8   4y  16y  16y  256y 8         n(n + 2)
                                                                6.
                 2.  (a)  210x   4    (b)  16 128x   2            3(2n + 1)(2n + 3)
                                             4
                         3 9
                  (c)  1760 a b          (d)  –945p q   6       7.  b 2
                  (e)  –20            (f)   36                  8.  11, 20
                                         x 3                    9.  Explicit formula: u  = 4n – 1
                                                                              n
                    5
                 3.  64x  +  160  +   20 7                       Recursive formula: u  = u n – 1  + 4 for n = 2, 3, 4, … and u  = 3
                                                                               n
                                                                                                      1
                           x
                        x
                 4.  14                                          or u n + 1  = u + 4 for n = 1, 2, 3, 4, … and u  = 3
                                                                         n
                                                                                               1
                 5.  15                                         10.  (a)  w  = 8n + 4
                                                                     n
                 6.  2                                           (b)  First term = 12; Common difference = 8
                 7.  n = 8, a = –  1                             (c)  S  = u + w  – 3

                           2                                    11.  11  n  n   n
                             2
                 8.  (a)  1 + 7x + 21x  + 35x   3                            3          3
                                                                                            3 2
                  (b)  1 + 7x + 14x  – 7x 3                     12.  (a)  U  = 23 1 +  1 24 , U  = 23 1 +  1 2  +  1 2 4 ,
                              2
                                                                                        5
                                                                             5
                                                                                            5
                                                                                 3
                                                                     2
                             2
                 9.  1 + 16x + 136x  + 784x  3                               3   3 2  3 3
                 10.  1 + 9x + 24x  2                               U  = 23 1 +  1 2  +  1 2   +  1 2 4
                                                                                 5
                                                                             5
                                                                     4
                                                                                      5
                 11.  (a)  –16 464    (b)  –151 164              (b)  lim U  = 5
                  (c)  –1760          (d)  26                       r → ∞  r
               Exercise 2.8                                     14.  (a)  (n + 1)(2n + 1)    (b)  –975
                 1.  (a)  1 – 2x + 3x  – 4x   3  (b)  1 + x + x  + x 3    15.  (a)  mn  1
                                               2
                             2
                                            1
                                                      1
                                                 3
                                                                                 2
                              2
                                                                              n
                  (c)  1 – 6x + 24x  – 80x 3  (d)  1 4  –   x +  16  x  –   x 3  (b)  mn – m + 1; S  =   m(2mn – m + 1)
                                                   2
                                                                         5
                                                      8
                                            4
                        2
                  (e)   1  –   x +   4   x  –   8   x 3         16.  (a)  u  =   2 4r + 1
                               2
                                                                     r
                     3  9    27   81
                                                                                                      279
       Answers STPM Math T S1.indd   279                                                               3/28/18   4:25 PM
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