由sin(α-β)=36/85得cos(α-β)=77/85,cosβ=4/5得sinβ=3/5sinα=sin[(α-β)+β]=sin(α-β)cosβ+cos(α-β)sinβ=77/85sinα=(2tan(α/2))/[1+(tan(α/2))^2]所以tan(α/2)=11/7或7/11cot(α/2+π/4)=tan(π/4-...