u=P(p)()T(t) ⊙(0)=(为常数) 2 ⊙n(0)=a'cos ne+b,sinn8,(n=1,2,…) o=(食p) Tn())=Cme u=之∑cnm4n=之之cn.(D(p)o.(0Tn(t) n=1n=0 ==0 之交((号小cmo+以nos 88 ( ) ( ) ( ) u P T t mn mn n mn 0 0 ( ) ( ) 2 ( ) cos sin ,( 1,2, ) n n n a a n b n n 为常数 1 0 1 0 ( ) ( ) ( ) mn mn mn mn n mn m n m n u c u c P T t ( ) ( ) n m P J mn n R 2 ( ) a t mn T t c e mn mn 2 ( ) 1 0 cos sin m n n m a t mn n n n m n c J a n b n e R