How to convert polar form equation rcos(θ)-sin(θ)=0 to rectangular form?

Question

I know that rcos(θ)-rsin(θ)=0 is really easy to be converted into rectangular form, so I wonder what should I do for the equation rcos(θ)-sin(θ)=0 ? (There is no "r" before sin(θ).)

Answer 1

x=r cos θ and y = r sin θ & you need to remember that r² = x² + y²

For this problem, x - y/sqrt(x² + y²)=0