问题描述: f(x)=sinx+cosx=根号2sin(x+pai/4) 是怎么样得来的呢? 1个回答 分类:数学 2014-10-01 问题解答: 我来补答 f(x) = sinx+cosx = √2(sinx (1/√2) + cosx (1/√2) )= √2(sinx cosπ/4 + cosx sinπ/4)= √2(sin(x+π/4)) 展开全文阅读