其中 ∫F z)coS nzz F(sin nzdz. T=兀 7x F(=f(r) f(x)=+∑(anc0s x+b, sinx) 2 其中 f(r)cos xdx bn=L/(x)sin/xdx( )sin . 1 ( )cos , 1    −  −  =  = b F z nzdz a F z nzdz n 其中 n F(z) f (x) l x z =   = ( cos sin ) 2 ( ) 1 0 x l n x b l n a a f x n n n  +  = +  = ( )sin . 1 ( )cos , 1   − −  =  = l l n l l n xdx l n f x l b xdx l n f x l 其中 a