余弦波计算Acos（wt + u) +Bcos(wt + z)请问如何化简.

Acos（wt + u) +Bcos(wt + z)
=A(coswtcosu-sinwtsinu)+B(coswtcosz-sinwtsinz)
=(Acosu+Bcosz)coswt-(Asinu+Bsinz)sinwt
=(1/((Acosu+Bcosz)^2+(Asinu+Bsinz)^2)^(1/2)cos(wt+m)
=Ccos(wt+m)
即为所求
其中C=(1/((Acosu+Bcosz)^2+(Asinu+Bsinz)^2)^(1/2)
=(A^2+B^2+2ABcos(u-z))^(1/2)
cosm=(Acosu+Bcosz)/C,sinm=(Asinu+Bsinz)/C