带入初始条件: =r+0=0 nJA A+2A,(r)cos 0 A=0 n=1 B,=Aa-sin OT =r+0 f(x, t)Bo+2nm B, (r)cos "nIm= cos i sinor B=Bn=0(m≠1) v(x, t; T)=A-sin atsina( cOS Al wa(t-T) (x,t)= cOS drain or sin Al t cosdrsin or[sin cOS zat cosdrSn[s(o+)z+so-)r]+cosa[eo(o+,)x-co(-,)]} 2 Al nat cossin cos(o+ coS(O Tat. 1 +cOS sin(@+)I带入初始条件： 0 v t= +0 = ( ) cos 0 1 0 + =  = l n x A A n n        ( ) cos cos sin 1 0 l x A l n x B l n a B n + n =  = ( , ) 0 v f x t t t= + = An = 0   1 sin a l B = A 0 ( 1) B0 = Bn = n  l x l a t a l v x t A       cos ( ) ( , ; ) sin sin − = l a t d l x a Al u x t t II ( ) ( , ) cos sin sin 0       − =  cos sin [sin cos cos sin ] 0 l a l at l a l at d l x a Al t           = −  cos {sin [sin( ) sin( ) ] cos [cos( ) cos( ) ]} 2 0                  l a l a l at l a l a l at d l x a Al t = + + − + + − −  sin( ) } 1 sin( ) 1 cos [ cos( ) ] 1 cos( ) 1 cos {sin [ 2 0 0 0 0 t t t t l a l l a a l l a at l a l l a a l l a at l x a Al                         − − + − + + − − − + + + − =