Question

Transform the equation $x^2+y^2=ax$ into polar form.

Answer 1

For conversion to polar form from Cartesian:
$x=r\cos \theta ,y=r\sin \theta$
$x^2+y^2=ax$
$⟹r^2{\cos }^2\theta +r^2{\sin }^2\theta =ar\cos \theta$
$⟹r^2=ar\cos \theta$
$⟹r=a\cos \theta$