Writing Consider the polar equation
$$
r=\frac{4}{1+e \sin \theta}
$$
(a) Use a graphing utility to graph the equation for $e=0.1$ $e=0.25, e=0.5, e=0.75,$ and $e=0.9 .$ Identify the conic and discuss the change in its shape as $e \rightarrow 1^{-}$ and $e \rightarrow 0^{+}$ .
(b) Use a graphing utility to graph the equation for $e=1$ . Identify the conic.