第1个回答 2019-05-01
(1)f(x)=sin^4(x/2)+(2√3)sin(x/2)cos(x/2)-cos^4(x/2)={sin^2(x/2)+cos^2(x/2)}(sin^2(x/2)-cos^2(x/2))+(2√3)sin(x/2)cos(x/2)=-cos^(x)+√3sinx=2sin(x-π/6)...注:sin^2(x/2)+cos^2(x/2)=1,三角函数基本公式;(2√3)sin(x/2)cos(x/2)=√3sinx,二倍角公式;-cos^(x)+√3sinx=2sin(x-π/6),三角函数和角公式。f(x)=2sin(x-π/6)最小正周期=2π
(2)g(x)=f(x)=2sin(1/2x-π/12),对称轴方程:1/2x-π/12=π/2+kπ,x=7/6π+2kπ