已知函数f(x)=sin(2x+π/6)+sin(2x+π/6)+2cos²x

问题描述:

已知函数f(x)=sin(2x+π/6)+sin(2x+π/6)+2cos²x

=2(sin2xcosπ/6+cos2xsinπ/6)+2cos²x
=2(√3/2sin2x+1/2cos2x)+2cos²x
=√3sin2x+cos2x+(1+cos2x)
=√3sin2x+2cos2x+1
也可以进一步化简 就是√7sin(2x+y)+1(这里y为一个特定值) 可以知道
f(x)范围是-√7到√7

多一个sin(2x+π/6)吧!f(x)=sin(2x+π/6)+2cos²x =sin2xcosπ/6+cos2xsinπ/6+1+cos2x =√3/2sin2x+3/2cos2x+1 =√3(1/2sin2x+√3/2cos2x)+1 =√3sin(2x+π/3)+1函数最小正周期T=2π/2=π...