Question

How do you convert `9r=4cos(theta)` into cartesian form?

Answer 1

`9x^2+9y^2-4x=0.`

Explanation:

To convert from Polar form to Cartesian, we need the following formula `(1) costheta=x/r, (2) sintheta=y/r,(3) r=sqrt(x^2+y^2).`

Using (1) in the given polar eqn. we have`9r=4x/r, or, 9r^2=4x,` & now by (3), `9(x^2+y^2)=4x, i.e., 9x^2+9y^2-4x=0.`