Question

将参数方程x=a(tanθ+1/cosθ),y=a/cosθ(θ为参数)化为普通方程

Answer 1

x=a(tanθ+1/cosθ)

= a(sinθ+1)/cosθ

= y*(sinθ+1)

即 sinθ = x/y - 1

又 y=a/cosθ 即 cosθ = a/y

由sin²θ+cos²θ=1得

(x/y - 1)² +a²/y² = 0

(x-y)²+a² = 0