Question

The letters r and θ represent polar coordinates. Write the equation using rectangular coordinates (x, y).

r = 8cos θ

Answer 1

When converting to polar, you have \(x=r\cos\theta\), right? How can you get an \(r\) on the right side?

Multiply both sides by \(r\):
\[r^2=8r\cos\theta\]
And what do you know about \(r^2\)?