原式=[(1-cosθ)+sinθ]/[(1+cosθ)+sinθ]+cot(θ/2)
=[2sin²(θ/2)+2sin(θ/2)cos(θ/2)]/[2cos²(θ/2)+2sin(θ/2)cos(θ/2)]+cot(θ/2)
=[2sin(θ/2)*(sin(θ/2)+cos(θ/2))]/[2cos(θ/2)(sin(θ/2)+cos(θ/2))]+cot(θ/2)
=sin(θ/2)/cos(θ/2)+cos(θ/2)/sin(θ/2)
=[sin²(θ/2)+cos²(θ/2)]/[sin(θ/2)cos(θ/2)]
=1/(1/2*sinθ)
=2cscθcsc是什么？沒學(xué)過啊、、、哦，那你就寫成2/sinθ，csc是余割函數(shù)，cscx=1/sinx哇，好高端，csc是什么時候要學(xué)的??？具體的我也忘了，應(yīng)該學(xué)到三角函數(shù)后期的時候就會學(xué)的吧=[sin²(θ/2)+cos²(θ/2)]/[sin(θ/2)cos(θ/2)]變成1/(1/2*sinθ)看不懂啊，能詳細講一下嗎？分子sin²(θ/2)+cos²(θ/2)=1

分母sin(θ/2)cos(θ/2)=1/2*2sin(θ/2)cos(θ/2)=1/2*sinθ，半倍角公式噢！懂了！聰明！最佳答案就你了??！