In order to graph a polar equation such as r = f(t) using a parametric equation grapher, you must replace this equation by x = f(t) cos t and y = f(t) sin t. These equations can be obtained by multiplying r = f(t) by cos t and sin t, respectively. Confirm the discussions of conics in the text by graphing r = 4e/(1 + e cos t) for e = 0.1, 0.5, 0.9, 1. 1.1 and 1.3 on [-π, π].