问题描述: Sina^4+2√3sinacosa-cos^4化简 1个回答 分类:综合 2014-09-19 问题解答: 我来补答 Sina^4+2√3sinacosa-cosa^4 =√3sin2a+(sina^2+cos^2)(sina^2-cosa^2)=√3sin2a+sina^2-cosa^2=√3sin2a-(cosa^2-sina^2)=2(√3/2sin2a-1/2cos2a)=2(sin2acosπ/6-cos2asinπ/6)=2sin(2a-π/6) 展开全文阅读