例3求fO)= sinkt(k为实数)的拉氏变换 +0O [sin kt]= sin ktest 1了j jkt jkt e Dedt (s-jk) dt 计+k)dt (s+jk) +oO 2S lo s+jk k 2s-jk s+jk 52+k214 例3 求 f(t)=sinkt (k为实数) 的拉氏变换 2 2 0 ( j ) 0 ( j ) 0 ( j ) 0 ( j ) 0 j j 0 j 1 j 1 2 j j 1 j 1 2 j e d e d 2 j (e e ) e d 2 j 1 [sin ] sin e d s k k s k s k e s k e s k t t t k t k t t s k t s k t s k t s k t kt kt s t s t +  =      + - - - =       + - - - - - =       - - = = - = + - + + - - + - + + - - + - - + -    L 