## Polar Equation

If I have 2 equations as shown below, how can I make them into 1 polar equation?

x(theta) = a*cos(theta) * sin(k*theta)
y(theta) = a * sin(theta) * sin(k*theta)

Thanks very much

 r = radius from x and y: $$r^2 = x^2 + y^2$$
 To maybe add a little to out's hint, square both of the equations you have and add them together. See what happens :).