Find a polar equation for the ellipse that has its focus at the pole and satisfies the stated conditions.
Enter t for the variable $\theta$.

(a) Directrix above the pole; $b =$ 5 and $e = \frac{3}{5}$.
Equation of the ellipse is $r=$

(b) Directrix to the left of the pole; $c =$ 3 and $e = \frac{1}{5}$.
Equation of the ellipse is $r=$