Question

How do you convert `r=cos(theta)` into cartesian form?

Answer 1

`x^2 + y^2 = x`

Explanation:

using the formulae that link Polar to Cartesian coordinates.

`• r^2 = x^2 + y^2`

`• x = rcostheta rArr costheta = x/r`

`• y = rsintheta`

for this question : `r = costheta`

then `r = x/r`

( multiply both sides by r )

hence `r^2 = r xx x/r rArr r^2 = x`

`rArr x^2 + y^2 = x`