= 0J()d=0 ak= f(t)cos(ka, td(@, t) ZI Jo E cos(ka, d(,t) 广 Em cos(k@,t)a(ao)] 2E Soc cos(ka,t)d(o, t)=0 be= f(t)sin(ko, t)d(@,t) [R Em Sin(ka, )d(@,t)- Em sin(ko, s)d(@, D)I 元 2E 2E z Jo sin(ko,td(@,t) cOS(KO t) k 2E m[1-cos(kz)I 兀( ) 0 1 0 0 =  = T f t dt T a   cos( ) ( ) 0 2 cos( ) ( ) cos( ) ( ) 1 ( )cos( ) ( ) 1 0 1 1 2 1 1 0 1 1 2 0 1 1 = = = − =                     k t d t E E k t d t E k t d t a f t k t d t m m m k   1 cos( )  2 cos( ) 2 1 sin( ) ( ) 2 sin( ) ( ) sin( ) ( ) 1 ( )sin( ) ( ) 1 0 1 0 1 1 2 1 1 0 1 1 2 0 1 1                      k k E k t k E k t d t E E k t d t E k t d t b f t k t d t m m m m m k = −       = = − = − =    