cos(x+π),cos(π-x)

化简:〔sin(3π-α)cos(π/2-α)〕÷〔tan(α-2π)xcos(π/2 α)
若x∈(0,π),cos(π-x)=2√2cos2x则sin2x=?
求函数fx=4cosxcos(x-α)在0≤x≤π/4的值域
当xy0π时如何计算cosxcosycosxy的范围
π/2 -π/2 (1 (sin x)^3)(cos x)^2dx