设g(x,t)=G(x)T(t)
U(x,t) = g(x,t) + v(x,t)
U(1,t)=0=g(1,t)=G(1)T(t),
G(1)=0
U(x,0)=1-x=G(x)T(0)+v(x,0);G(0)+0=1-0=1;G(0)=1
U(0,t)=cos(t)=G(0)T(t)=T(t);T(0)=1
g(x,t)=G(x)T(t)=[1-x-v(x,0)]cos(t)
如果设 v(x,0)=0
g(x,t)=[1-x]cos(t)