Question

How do you convert `r = 2a cosθ` into a cartesian equation?

Answer 1

`x^2+y^2=2ax`

Explanation:

Multiply both sides by `r` to get `r^2=2arcostheta`. Use the fact that `r^2=x^2+y^2` and that `x=rcostheta` to get `x^2+y^2=2ax`.