Page 42 - ACE YR IGCSE A TOP APPR' TO ADD MATH
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                            1
                                    3
                                  2
                               1
                    5.  Area =    x   x   x  x 1                          AC = √(x – 3)  + (y – 0)
                                                                                2
                                                                                          2
                            2  y   y   y   y 1                                1 = x  – 6x + 9 + y
                               1
                                  2
                                    3
                                                                          x  – 6x + y  + 8 = 0 …… (1)
                                                                                  2
                                                                           2
                            1
                        5.5 =    1 –2  d 1
                            2  3 –1 4 3                                    2x  – 2  =  y
                        11 = |−1 − 8 + 3d − (−6)−(−d) − 4)|                 3      2
                        11 = |–7 + 4d|                                      4x – 12  = 3y
                                                                                   4x – 12
 =  1                  −7 + 4d = 11                                            y  =   3   …… (2)
 2                         d = 4.5                                        Substitute equation (2) into (1):
 = √3                  –7 + 4d = –11                                                       4x – 12  2
                                                                                   2
                           d = –1                                                 x  – 6x +  3  3  4   + 8 = 0
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 = √(7)  –                                                  [2]             9x  – 54x + 16x  – 96x + 144 + 72 = 0
 2
                                                                                       2
                                                                             2
                                                                                          2
                    6.  y = x  – 9x – 10                                               25x  – 150x + 216 = 0
                          2
 2
 2
 =  1 8  + 3          dy  = 2x – 9                                        x =   –b ± √b  – 4ac
                                                                                    2
 2
 1                    dx                                                           2a
 = 2  2               Gradient of the tangent line at point A:                –(–150) ± √(–150)  – 4(25)(216)
                                                                                             2
 =                     m m  = −1                                            =            2(25)
                          2
                        1
                         m  = –1 ÷  1                                         18       12
                          1      2                                        x =     or  x =
                            = –2                                              5        5
                                                                              4
                      2x – 9 = –2                                         y =     or  y = –   4
                                                                                        5
                                                                              5
                             7
                          x =
                             2                                            C 1 18 4 2  (invalid, as it is not on AB) or
                                                                               ,
                                                                             5
                                                                                5
                                 7
                          7
                      y =  1 2 2  – 9 1 2  – 10                           C 1 12 –4 2 .
                                 2
                          2
                                                                               ,
                        =  –117                                              5  5                           [10]
                           4
                      Equation of the normal line:                     (b)  m m  = –1
                                                                            1
                                                                              2
                          y  = mx + c                                       m   = –1 ÷  4
                                                                              2
                      –117   =  1 7   + c                                          3  3
                               1 2
                        4     2 2                                               = –  4
                          c  = –31
                                                                             4
                                                                                    1 2
                              1                                             –    = –  3 12   + c
                          y  =  x – 31                                       5     4 5
                              2
                                                            [5]               c  = 1
                                                                                   3
                    7.  (a)  Point A:                                         y  = –  x + 1
                                                                                   4
                          2x  – 2 =  0                                                                       [2]
                          3      2
                             2x  = 2                                 8.  (a)  m  =   –10 – 3
                                                                            1
                             3                                                  0 – 7
                              x = 3                                          = 1
                         A(3, 0)                                          m m  = –1
                                                                            1
                                                                              2
                                                                            m   = –1
                                                                              2
                         Point B:                                           y = mx + c
                          2(0)  – 2 =  y                                   –3 = (–1)(7) + c
                           3      a                                         c = 4
                               y = –2a                                    \  y = –x + 4
                         B(0, –2a)                                                                           [2]
                                                                                 1 0  0    7 0
                         Distance AB:                                  (b)  Area =
                              5 = √(3 – 0)  + (0 – (–2a))                        2 0 –10 –3 0
                                                  2
                                       2
                                                                                 1
                              5 = √9 + 4a                                      =   |–70|
                                       2
                                                                                 2
                          25 – 9 = 4a                                          = 35 unit
                                   2
                                                                                      2
                              a = 2  or  a = –2 (invalid)                                                    [2]
                         Cambridge IGCSE
                                          TM
                  182     Ace Your Additional Mathematics
         Answers Add Math.indd   182                                                                             14/03/2022   12:29 PM
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