设函数f(x)=根号3cos^x+sinxcosx-根号3/2

1个回答

  • 解 f(x)=√3cos²x+sinxcosx-√3/2

    =√3*(1+cos2x)/2+(1/2)sin2x-√3/2

    =(1/2)sin2x+(√3/2)cos2x

    =sin(2x+π/3)

    ∴T=π

    单增区间:-π/2+2kπ≤2x+π/3≤π/2+2kπ,k∈Z

    -5π/6+2kπ≤2x≤π/6+2kπ,k∈Z

    -5π/12+kπ≤x≤π/12+2kπ,k∈Z

    即为:[-π/12+kπ,5π/12+kπ],k∈Z

    (2)结合图像,5π/12+17π/12+29π/12=51π/12