d u+ 0 d x 即么2 p)=4/p 通解:n(xp)=24+c( shIPs+c(khyx即 0 2 ~ 0 2 2 2~ - + = a u u a p dx d u (0, ) 0, ~ ux p = u(l, p) u / p ~ = 1 ( ) ( ) ( ) x a p x c p a p c p p u : u x, p 1 sh 2 ch 0 \通解 = + +