已知tana/2=根号5求(1+sinα-cosα)/(1+sinα+cosα)

因为1=[sin(α/2)]^2+[cos(α/2)]^2, sinα=2sin(α/2)cos(α/2), cosα=[cos(α/2)]^2-[sin(α/2)]^2(1+sinα-cosα)/(1+sinα+cosα)={[sin(α/2)+cos(α/2)]^2-[[cos(α/2)]^2-[sin(α/2)]^2]} / {[sin(α/2)+cos...