求证tanθ+secθ=tan(θ/2+π/4)
问题描述：
求证tanθ+secθ=tan(θ/2+π/4)
答
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 ...