1)形式1 f() do+>(ak cos kat+bk sin kat) k=1 2∫ T f(t)dt 式中 h÷<P f(tcos k tdt T 2 k f(t)sin katt TJo1）形式1 0 1 ( ) ( cos sin ) 2 k k k a f t a k t b k t    = = + +  0 0 2 ( ) T a f t dt T =  f t k tdt T a T k ( ) cos  2 0 = f t k tdt T b T k ( )sin  2 0 = 式中