已知函数f(x)=cos²x-√3sinxcosx+1求函数f(x)的单调递增区间.若f(θ)=5/6,θ∈(π/3,2π/3),求sin2θ的值.
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![已知函数f(x)=cos²x-√3sinxcosx+1求函数f(x)的单调递增区间.若f(θ)=5/6,θ∈(π/3,2π/3),求sin2θ的值.](/uploads/image/z/4346398-46-8.jpg?t=%E5%B7%B2%E7%9F%A5%E5%87%BD%E6%95%B0f%28x%29%3Dcos%26%23178%3Bx-%E2%88%9A3sinxcosx%2B1%E6%B1%82%E5%87%BD%E6%95%B0f%28x%29%E7%9A%84%E5%8D%95%E8%B0%83%E9%80%92%E5%A2%9E%E5%8C%BA%E9%97%B4.%E8%8B%A5f%28%CE%B8%29%3D5%2F6%2C%CE%B8%E2%88%88%EF%BC%88%CF%80%2F3%2C2%CF%80%2F3%EF%BC%89%2C%E6%B1%82sin2%CE%B8%E7%9A%84%E5%80%BC.)
已知函数f(x)=cos²x-√3sinxcosx+1求函数f(x)的单调递增区间.若f(θ)=5/6,θ∈(π/3,2π/3),求sin2θ的值.
已知函数f(x)=cos²x-√3sinxcosx+1
求函数f(x)的单调递增区间.
若f(θ)=5/6,θ∈(π/3,2π/3),求sin2θ的值.
已知函数f(x)=cos²x-√3sinxcosx+1求函数f(x)的单调递增区间.若f(θ)=5/6,θ∈(π/3,2π/3),求sin2θ的值.
(1)f(x)=(1+cos2x)/2-3^1/2/2sin2x+1
=-sin(2x-pai/6)+3/2
t=sin(2x-pai/6)
f(t)=-t+3/2
f(t)在R上是单调递减的
f(t)的单调递增区间就是t(x)的单调递减区间
2kpai+pai/2