Question

How do you convert `r=8cos(theta)` into cartesian form?

Answer 1

`x^2+y^2=8x`

Explanation:

As relation between Cartesian coordinates `(x,y)` and polar coordinates `(r,theta)` is given by `x=rcostheta` and `y=rsintheta` i.e. `r^2=x^2+y^2`.

As `r=8costheta` can be written as

`r×r=8rcostheta` or

`r^2=8rcostheta` or

`x^2+y^2=8x`

Note - This is the equation of a circle with center at `(4,0)` and radius `4`.