题目

求证tanθ+secθ=tan(θ/2+π/4)

提问时间：2021-03-21

答案

tanθ+secθ=sinθ/cosθ+1/cosθ=(sinθ+1)/cosθ=[cos(π/2 -θ)+1]/sin(π/2 -θ)=2cos²(π/4 -θ/2)/[2sin(π/4 -θ/2)cos(π/4 -θ/2)]=cos(π/4 -θ/2)/sin(π/4 -θ/2)=cot(π/4 -θ/2)=tan[π/2-(π/4 ...