问题描述: 求y=sin^4(x/4)+cos^4(x/4)的导数 , 1个回答 分类:数学 2014-12-10 问题解答: 我来补答 y=sin^4(x/4)+cos^4(x/4)=sin^4(x/4)+cos^4(x/4)+2sin^2(x/4)cos^2(x/4)-2sin^2(x/4)cos^2(x/4)=[sin^2(x/4)+cos^2(x/4)]^2 -1/2 sin^2(x/2)=1 -1/2 sin^2(x/2)所以求导,得y'=-1/2 ×2sin(x/2)×cos(x/2)×1/2=-1/2sin(x/2)cos(x/2)=-1/4sinx 展开全文阅读