已知f(x)=√3sin(x+θ)+cos(x-θ)是偶函数,0＜θ＜x,求θ
问题描述：
已知f(x)=√3sin(x+θ)+cos(x-θ)是偶函数,0＜θ＜x,求θ
是0＜θ＜π
答
f(x)=√3sin(x+θ)+cos(x-θ)是偶函数,即f(-x)=f(x)f(-x)=√3sin(-x+θ)+cos(-x-θ)=-√3sin(x-θ)+cos(x+θ)=√3sin(x+θ)+cos(x-θ)即：cos(x+θ)-cos(x-θ)=√3sin(x+θ)+√3sin(x-θ)即：-2sinxsinθ=2√3sinxco...