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Form Five                                                            Form Five


          Derivatives of exponential functions
          Teaching steps

             1.  Guide students through discussions to deduce derivatives of
                       sin xx ⎣FOR ONLINE READING ONLY
                 exponential functions. Engage students in groups to perform
                 Activity 8.5 on recognizing the derivative of an exponential
                 function.  Advise  students  to  share  their  findings  through
                 presentations.
             2.  Use Examples  8.46 to 8.49 in the  Student’s Book to guide
                 students  and  assist  them  on  how  to  find  derivatives  of
                 exponential functions. Engage students to verify the solutions
                 by using mathematical software.

             3.  Assign students to attempt Exercise 8.12 in the Student’s Book.
                 Advise students to submit their work; check the correctness of
                 their answers, and provide them constructive feedback.



          Answers to Exercise 8.12

                                                                        )
                                                                       2
                               2
                                                   ′
                              x
            1.  (a)  f ′ () 2x =  xe          (b)  ( )gx = e x  ( 1 12x−  −  6x
                                      ⎞
                     ′
                     ( ) e=
               (c)  hx      x ⎛  ⎜  1  + ln x    (d)   fx =  x 3 9 ln9 9 3x+  x  2
                                      ⎟
                                                   1
                                                             x
                                                    ( )
                             ⎝  x     ⎠
            2.  y′ = (cos x − sin 2  ) xe cosx    5.   f ′ () 2x =  xe +  x e
                                                                 2 x
                                                            x
                                                              2x
                            ( )
                                   2
            6.  (a)  y′ =  4sin 8xe sin 4x      (b)   y′ =  (2ln3 )3
                                   x
                                                         2
               (c)   y′ = (1 x+  ln  ) 3 3         (d)   x′ = sec θ e tanθ
                                                                      2
                          2
               (e)  x′ = 3t + 6te − 3t 2  + sec tant  t    (f)  v′ = (2u +  ) 2 e u + 2u− 8
                    x 3 ln 2x ⎡  3  1            ⎤
            10.  y′ =       ⎢  +        −−       ⎥
                                         1 cot x
                    e x          x ln 2x         ⎦
                                  161
                                             Mathematics for Advanced Secondary Schools
                                                                        30/06/2024   18:02:41
   ADVANCED MATH F.5 TG CHAPTERS.indd   161                             30/06/2024   18:02:41
   ADVANCED MATH F.5 TG CHAPTERS.indd   161
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