4 E dxdvsin Axyl-x(l-y) 00 64Al (2k+1)(2+1)3x° n”k=0(2k+1)(22+)3c0 64A14 1(xy:1)=0。∑ (2k+1)2+(2q+1)2at(2k+1) sIn S)(2q+1)zysin sin ( )( ) 4 0 0 2 Axy l x l y l n y l m x dxdy l E l l mn = − −    . (2 1) (2 1) 64 3 3 6 4 + +  = k q Al   = + + + + + + + = , 0 2 2 6 3 3 4 (2 1) sin (2 1) sin (2 1) (2 1) cos (2 1) (2 1) 64 1 ( , , ) k q l q y l k x l k q at k q Al u x y t   