化简cos27°sin(a-63°)-cos63°sin(a+27°)

问题描述:

化简cos27°sin(a-63°)-cos63°sin(a+27°)
RT

cos27°sin(a-63°)-cos63°sin(a+27°)
=sin63sin(a-63)-cos63cos(a-63)
=-cos(63+a-63)
=-cosa