d-X day k r(x) d-z d d d=2=-p2z(= x()=x(4)=0y(0)=y(8)=0(z(0)=0 X(x)=A x,k nt ,(m=1,2,3 A ()=A,si (m=12,3 B k2+12+p2=0 Z(E=Ch sinhvk2+12z 16 p(x,y,2)=2Cm sin "m xsin m ysih n+ m ne mmtsinh n,m-=1 B( )   ( ) ( )    = = = − 0 0 d d 2 2 2 X X A k X x x X ( )   ( ) ( )    = = = − 0 0 d d 2 2 2 Y Y B l Y x y Y ( )   ( )    = = − 0 0 d d 2 2 2 Z p Z z z Z 0 2 2 2 k +l + p = ( ) ( )  ( ) ( )     = = =  = = =  , m , , , A m y , l B m Y y A , n , , , A n x , k A n X x A 1 2 3 π π sin 1 2 3 π π sin 2 1 Z(z) C k l z kl 2 2 = sinh + ( )                +      =   = z B m A n y B m x A n x, y,z C n,m n m sinh π π sin π sin 2 2 1                 +      = C B m A n mn Cmm π sinh π 16 2 2 2 0