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Mathematics Term 1  STPM  Answers
             Exercise 6.7                                     21.  (b)  3 26 unit 2  (c)  5 i +  j –   13 k
                                                                                          1
               1.  (1, –2, 5)                                                         4   8   4
               2.  (4, 5, 9)                                   (d)   35 16 201
                                                                    16 201
               3.  (a)  (–3, 1, 5)   (b)  (3, –5, 4)             1     9
               4.  (a)  l  = 2, l  = 1   (b)  c = –5          22.   1 2 1 2
                                                                –1   + t 14   where t ∈ R
                   1
                        2
                (c)  (2, –3, –3)                                 0     1
               5.  (5, –3, 7)                                 23.  (1, 2, 3)
               6.  (1, –5, 1)                                 24.  47°7´
               7.  (2, 14, 6)                                 25.  8i + 4j – 4k, –8i + 12j + 16k
                                        5
                                     y +     z –   13
               8.  x =   2y + 5   =   2z – 13  or x =   2   =   2  ,    26.  2i – 3j + 4k
                    7
                           –17
                                      7     –  17             27.  (a)  22 units   (b)  12i – 15j – 9k
                                      2       2
                    5
                                7
                r = –   j +   13  k + l(i +   j –   17  k)    28.  (a)   7 390     (b)  1   329 unit 2
                    2   2       2    2                             390                2
                                                                   .
                                                               (c)  r   (–10i – 15j + 2k) = –30
                       4
                    y +     z +   8                           29.  (a)  13x – 2y + 5z = –4   (b)  (–1, –22, –7)
               9.   x 1   =   3   =   3                        (c)  14.9°
                     5       1
                     3       3
                                                              STPM Model Paper (954/1)
               10.   x – 11   =   y + 8   = z
                  4     –3                                    1.  (a)  f : x ↦ x  – 6x = (x – 3)  – 9
                                                                                  2
                                                                        2
             STPM PRACTICE 6                                                      y
                                                                             y = f(x)
               1.  (a)  474  units   (b)  46 units                                         y = k
               2.  (a)  –i – 4j – 2k   (b)  –5i – 7j + 11k                                x
               3.  (a)   1   (5i – j – k)  (b)  1   (–i – j + 3k)                0     3
                   27                   11
               4.  (a)   2   (i + j – k)  (b)  5   (–3i – j – k)                        (3, –9)
                    3                   11
                                                                  Any horizontal line y = k is drawn horizontally with
               5.  (a)  –8          (b)  4                        x-axis, will cut the graph at only one point.
                                                                                              –1
               6.  (a)  83°44´      (b)  127°25´                  Therefore f is a one-to-one function and f  exists.
               7.  (a)  78.7°       (b)  36.8°                    (shown)
                                                                         –1
                                                                     Let  f (x) = y
                                        –1
                                        7
               8.  (a)  p = 1 ; q = –1   (b)   1 2                         x = f(y)  2
                                                                           x = (y – 3)  – 9
               9.  35°                  –2                             ± x + 9  = y – 3
                   →
               10.  (a)  PQ = –6i + 6j + 12k   (b)  61.9°                   y = 3 –  x + 9  as y < 3
                                                                          –1
                   →                                                     f (x) = 3 –  x + 9
                    PR  = 6i + 6j + 12k
                                                                           –1
                                                                           f  : x ↦ 3 –  x + 9

               11.  (b)  58.7°                                            D –1 = [–9, ∞)
                            1
                (c)  152 unit , 25  unit 3                                 f
                         2
                            3                                             R –1 = (–∞, 3]
                                                                           f
               12.  (a)  –2i + j + 4k   (b)  –4i + 4j – 8k     (b)         y
                  1
               13.  ±    (–2i + j + 4k)
                  21                                                      4       g(x) = 4 – e –x
               14.  41 unit 2                                             3
               15.  (a)  11i – 29j + 5k  (b)  1    987 unit 2
                                       2                                            x
               16.  (a)   5         (b)  3                                0
                   18                  10                         R = (–∞, 4)

                   1                                               g
               17.  (a)    (3i – 4j + 6k)   (b)  8i + (4 + l)j + 8k     R = (–∞, 4) ⊄ D  = (–∞, 3]
                                                                              f
                                                                   g
                   61
                (c)  l = –9                                       Therefore fg does not exist. (shown)
               18.  (a)  a = 10, b = 2   (b)  64.4°               We need R = (–∞, 3]
                                                                         g
                                                                         –x
               19.  (b)  x + y – 3z = 7                                 4 – e  < 3
                                                                         x < 0
               20.  Yes                                           Therefore the maximum domain of g for which fg exists
                                                                  = (–∞, 0]
             288
       Answers STPM Math T S1.indd   288                                                               3/28/18   4:25 PM
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