1、两角和公式sin(A+B) = sinAcosB+cosAsinBsin(钽吟篑瑜A-B) = sinAcosB-cosAsinBcos(A敫苻匈酃+B) = cosAcosB-sinAsinBcos(A-B) = cosAcosB+sinAsinB
2、倍角公式Sin2A=2SinA•CosACos2A = Cos2A-Sin2A=2Cos2A颍骈城茇-1=1-2sin2A积化和差Sinasinb = -[cos(a+b)-cos(a-b)]Cosacosb = [cos(a+b)+cos(a-b)]Sinacosb = [sin(a+b)+sin(a-b)]Cosasinb = [sin(a+b)-sin(a-b)]
3、诱导公式sin(π-a) = sinacos(π-a) = -cosasin(π+a) = -sinacos(π+a) = -cosa
