已知函数f(x)=4sin(π-x)cos(x-2π)

问题描述:

已知函数f(x)=4sin(π-x)cos(x-2π)
若θ∈(0,π) f(θ+π/4)=2/3 求sinθ

f(θ+π/4)=4sin(π-(θ+π/4))cos((θ+π/4)-2π)=2/3