-lx P=X(r(y) (x=Ae Be r(y)=Csin hy+Dcos hy P(x,y)=(Ae Be (csin ky+Dcos ky) (3)确定常数A,B,C,D,k ①y=0,0=0→D=0 ②y=b,q=0→ sin kb=0 kb=n丌k 1三 b 0,(x,y)=(Ae+B,e Cn sin ky) )( 通解q(x,y)=∑qn(x,y)( ) ( ) ( ) ( ) sin cos kx kx X x Ae Be X x Y y Y y C ky D ky  −  = + =   = +  ( , ) ( )( sin cos ) kx kx x y Ae Be C ky D ky −  = + + （3）确定常数 A，B，C，D，k ① y = 0, = 0  D = 0 ② y b kb = =  = , 0 sin 0  ( 1,2,3, ) n kb n k n b  = = =  ( , ) ( )( sin ) ( 1,2,3 ) n n n n kx kx x y A e B e C ky n −  = + =    = = 1 ( , ) ( , ) n n 通解  x y  x y 机动 目录 上页 下页 返回 结束