Help with these questions and steps if you don't mind pls.

4. Are there any horizontal or vertical tangent lines to the curve x = t +et, y = t - et? If so, for what values of t? If not, show that there isn't. [5 points] 5. Rewrite the polar equation r sin 0 = Inr + In cos 0 in Cartesian form as y = f(x). [5 points]