Question

化简cos27sin(α-63)-cos63sin(α+27)=?有什么便捷的方法吗?

Answer 1

.cos27sin(α-63)-cos63sin(α+27)=sin(a-63)cos27-sin27cos(63-a)=sin(a-63)cos27-sin27cos(a-63)=sin(a-63-27)=sin(a-90)=-cosa