(x,y)=(x2+y2)+(x-y)=p2+Pcos2 △(x p=-C、q b Po cos 2o w(p,p)=Co+Do In p+2(mp"m+Dmp m)(An cos mg+mn sin mp) w(P,)=Co+Ep"(A, cosmo+B, sin mp m= 边界条件 w(Po, )=Co+2Po"(Am, cos mp +Bm sin mo b 4 po cos 20 12 C- Po2 2 4 4 2 4 ( , ) ( ) ( ) cos 2 4 12 4 12 a b a b v x y x y x y = + + − = +     = w x y ( , ) 0 0 2 4 0 0 cos 2 4 12 a b w c  = = − −    0 0 1 ( , ) ln ( )( cos sin ) m m m m m m m w C D C D A m B m         − = = + + + +  0 0 0 1 ( , ) ( cos sin ) m m m m w C A m B m       = = + +  2 4 0 0 cos 2 4 12 a b = − − c    2 0 0 4 a C c = −  0 1 ( , ) ( cos sin ) m m m m w C A m B m       = = + +  边界条件