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CHAP. 21]                       THE LAPLACE TRANSFORM                                 221



               respectively,





                                                           be
                                            2
         21.26.  Find the Laplace transforms  of (a) 6 , (b) cos ad, (c) e  sin ad, where a and b denote  constants.
                  Using entries 3 (with n = 3), 9, and  15 of Appendix A with x replaced  by 6, we find  the Laplace transforms to
               be, respectively.





                                     Supplementary Problems


         In Problems 21.27  and 21.42, find  the Laplace  transforms of the given function  using Eq.  (21.1).

         21.27.  f(x)  = 3

                    2
         21.29.  f(x)  = e *                        21.30.  f(x)  = e~ 6x
         21.31.  f(x)=x                             21.32.  f(x)  = -Sx

         21.33.  f(x)  = cos3x                      21.34.  f(x)  = cos4x
         21.35.  f(x)  = cos bx, where b denotes a constant  21.36.  f(x)=xe- 8x

                     bx
         21.37.  f(x)  = xe , where b denotes a constant  21.38.  f(x)=x 3






         21.41.  f(x)  in Fig.  21-4                21.42.  f(x)  in Fig.  21-5

         In Problems 21.43  and 21.76, use Appendix A and the Properties 21.1 through 21.6,  where appropriate, to find  the  Laplace
         transforms  of the  given functions.






















                                                  Fig.  21-4
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