a=(根号3cosx,cosx-1)b=(sinx,cosx+1)函数f(x)=ab+1/2 求f(x）周期
问题描述：
a=(根号3cosx,cosx-1)b=(sinx,cosx+1)函数f(x)=ab+1/2 求f(x）周期
答
f(x)=√3cosxsinx+(cosx-1)(cosx+1)+1/2
=√3cosxsinx+cos²x-1+1/2
=√3/2sin2x+(1+cos2x)/2-1/2
=√3/2sin2x+1/2cos2x
=sin(2x+π/6)
T=2π/2=π
周期π