已知函数f(x)=2cos(x+三分之派)【sin(x+三分之派)-根号3cos(x+三分之派)】,求函数的最小正周期和单调递减区间
问题描述:
已知函数f(x)=2cos(x+三分之派)【sin(x+三分之派)-根号3cos(x+三分之派)】,求函数的最小正周期和单调递减区间
答
f(x)=2cos(x+π/3)[sin(x+π/3)-√3cos(x+π/3)]=2cos(x+π/3)sin(x+π/3)-2√3cos²(x+π/3)=sin(2x+2π/3)-√3[1+cos(2x+2π/3)]=sin(2x+2π/3)-√3cos(2x+2π/3)-√3=2[(1/2)sin(2x+2π/3)-(√3/2)cos(2x+2π...