化简sin(π/4+a)+sin(π/4-a)

问题描述:

化简sin(π/4+a)+sin(π/4-a)

sinπ/4=√2/2
所以原式=sinπ/4cosa+cosπ/4sinπ/4+sinπ/4cosa-cosπ/4sinπ/4
=2sinπ/4cosa
=√2cosa什么公式啊和角公式,采纳吧