已知函数f(x)=sin(x-θ) cos(x-θ)(x≠kπ,k属于Z)为偶函数说明y轴是对称轴f(x)=sin(x-θ) cos(x-θ)=sin(2x-2θ)/2故f(0)=sin(-2θ)/2=±1/2所以sin2θ=±1所以2θ=kπ+π/2所以θ=kπ/2+π/4,k∈Z如果不懂,祝学习...