f(t=a,+a, cos(@, t)+b, sin(@, o]+[a, cos(2@, )+b, sin(2@, o]+ +a, cos(ka, t)+bk sin(ko, o]+ ao+> acos(ka, t)+b sin(ka,o) 上式中的系数,可由下列公式计算 ao=f(tdt=3(t)dt k f(t)cos(ka,t)dt f(tcos(ka,t)dt z o J(O)cos(ka,(d(@)=T 2兀 f(tcos(ko,t)d(o,t) b:T/()sin(ko, t)dt =f()sin( ko, t)dt 2 d f(t)sin(ko, t)d(o, t)=rr f(t)sin(ko, t)d(@t 上述计算式中k=1,2,3,上式中的系数，可由下列公式计算： 上述计算式中k=1, 2, 3, …   − = = 2 2 0 0 ( ) 1 ( ) 1 T T T f t dt T f t dt T a ( )cos( ) ( ) 1 ( )cos( ) ( ) 1 ( )cos( ) 2 ( )cos( ) 2 1 1 2 0 1 1 2 2 1 0 1     − − = = = =            f t k t d t f t k t d t f t k t dt T f t k t dt T a T T T k ( )sin( ) ( ) 1 ( )sin( ) ( ) 1 ( )sin( ) 2 ( )sin( ) 2 1 1 2 0 1 1 2 2 1 0 1     − − = = = =            f t k t d t f t k t d t f t k t dt T f t k t dt T b T T T k        cos( ) sin( ) cos( ) sin( ) ( ) cos( ) sin( ) cos(2 ) sin(2 ) 1 1 1 0 1 1 0 1 1 1 1 2 1 2 1 a a k t b k t a k t b k t f t a a t b t a t b t k k k k k         = + + + + + = + + + + +   =  