f(x)=sinx+cosx=根号2sin(x+pai/4) 是怎么样得来的呢?
问题描述：
f(x)=sinx+cosx=根号2sin(x+pai/4) 是怎么样得来的呢?
答
f(x)=根号2*[根号2/2*sinx+cosx*根号2/2]
=根号2*[cos(π/4)*sinx+cosx*sin(π/4)]
=根号2*sin(x+π/4)
答
f(x) = sinx+cosx
= √2(sinx (1/√2) + cosx (1/√2) )
= √2(sinx cosπ/4 + cosx sinπ/4)
= √2(sin(x+π/4))