江画工太猩院 u=sint+sin 3t+sin 5t+sin t+sin 9+) 0.5 t 1 3 u(t =-(sint+sin 3t+sin 5t+=sinit+ . (-π<t<兀,t≠0)江西理工大学理学院 sin7 ) 71 sin5 51 sin3 31 (sin 4 ( ) + + + +L π u t = t t t t (−π < t < π,t ≠ 0) sin9 ) 91 sin7 71 sin5 51 sin3 31 (sin 4 u t + t + t + t + t π =