已知α是第二象限角,则sin(α-2π)/√[1-cos^2(-α)]+2√[1-cos^2(π/2+α)]/sin(α-3π/2)

问题描述:

已知α是第二象限角,则sin(α-2π)/√[1-cos^2(-α)]+2√[1-cos^2(π/2+α)]/sin(α-3π/2)