式中,ao2a,b称为付里叶系数可由下列积分求得 7Jo/(Odt=Ir2m f(td(at) 2丌 f(t)cos kott f(tcos kotd(ot) 2丌 f(tsin kotdi f(tsin katd(at) 式(6-1)和式(6-2)各系数之间存在如下关系 Ao 6-4 k= arctan k式中, a0 , ak , bk称为付里叶系数,可由下列积分求得:       = = = = = =              2 0 0 2 0 0 2 0 0 0 ( )sin ( ) 1 ( )sin 2 ( )cos ( ) 1 ( )cos 2 ( ) ( ) 2 1 ( ) 1 f t k tdt f t k t d t T b f t k tdt f t k t d t T a f t dt f t d t T a T k T k T (6 — 3) k k k km k k b a A a b A a arctan 2 2 0 0 = = + =  式（6 — 1）和式（6 — 2）各系数之间存在如下关系: (6 — 4)