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Additional Mathematics SPM  Chapter 1  Functions
                5.  The functions g and h are defined as      PAPER 2
                                x
                                              2
                          g(x) =    – 1 and h(x) = x  – x
                               2                                1.  The functions f and g are defined as
                  respectively.                                           2x
                                                                                            x + 1
                  (a)  Find g (x).                                  f(x) =   x + 1 , x > 0 and g(x) = ABBBB, x . −1
                           –1
                                     –1
                  (b)  Solve for gh(x) = g (x).
                                                                 respectively.
                6.  The  following  diagrams  show  four  different  graphs.
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                  In  each  case,  the  entire  graph  is  shown  and  the   (a)  Find fg(8).
                                                                                          2
                  scale on both axes are the same.               (b)  Write an expression for f (x). Give your answer
                                                                                   ax
                  A        y                                         in  the  form  of   bx + c  ,  where  a,  b  and  c  are
                                                                     constants.
                                                                 (c)  Write an expression for g (x). Hence, state its
                                                                                          –1
                                x
                          O                                          domain and range.
                                                                 (d)  The  following  diagram  shows  the  graph  of
         Form 4
                                                                     y = g(x).
                  B        y
                                                                            y
                                                                            7
                                x
                          O                                                 6
                                                                            5
                                                                            4
                                                                            3
                  C     y                                                   2                y = g(x)
                                                                            1
                                                                                                    x
                                                                          –1  0  1  2  3 4 5 6  7 8  9
                                x
                       O
                                                                     On  the  same  axes,  sketch  the  graph  of
                  D       y                                          y = g (x).
                                                                         −1
                                                                2.  In  the  Beijing  2008  Olympics,  Usain  Bolt,  or  also
                                x                                known  as  ‘Lightning  Bolt’,  had  set  a  world  record
                          O
                                                                 in  a  100  m  race  at  9.69  seconds.  However,  in  the
                                                                 last 20 m of the race, Bolt was seen looking around,
                                                                 and  after  knowing  that  he  was  leading  the  other
                  In the table below, mark ✓ for the correct relation for   racers  by  quite  a  distance,  Bolt  slowed  down  and
                  each graph, if any.                            started  celebrating  his  victory.  His  coach  claimed
                                                                 that if Bolt maintained his speed for the entire race,
                                             A  B   C  D         he  could  have  recorded  a  better  run  time  of  9.52
                   Not a function                                seconds. A group of physicists, led by Hans Kristian
                                                                 Eriksen,  have  investigated  the  claim.  They  found
                   One-to-one function                           that in most of Bolt’s races, his position, in m, can be
                   A function which is its own                   represented by a function s(t) = 11.8t – 12.5, where t
                   inverse                                       is the time, in seconds.
                   A function which does not have                (a)  Suggest  one  reason  why  the  domain  of  this
                                                                     function need not necessarily begin at t = 0.
                   an inverse                                    (b)  Determine the inverse function of s(t).
                                                                 (c)  What is represented by the inverse function in
                7.  The functions f and g are defined as f : x → x – 3   (b)?
                  and g : x → x  respectively. Find              (d)  Use  the  inverse  function  in  (b)  to  determine
                            2
                  (a)  gf(x),                                        whether the claim by Bolt’s coach was true.
                                        2
                  (b)  h(x) such that hgf(x) = x  – 6x + 3.






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