to +t 0 「 cos na,t sin mo=0所有m,n +7 m n cos no, t cos m@, tdt=2 0 m≠n +7 sin no,t Sin ma,tdt =12 n m≠ncos 1 .sin 1 0 0 1 0 n t m tdt t T t n t m tdt t T t 1 1 cos .cos 0 1 0 m n T 2 1 0 m n n t m tdt t T t 1 1 sin .sin 0 1 0 m n T 2 1 0 m n 所有m,n