Need help having trouble with this question....

a) Find gradient at the point where theta=pi

b) Hence find the cartesian co-ordinates

c) Find equations of the tangent and normal at this point.

My workings

a)

as tan pi = 0, i will get an undefined answer is so how can i do the following parts? :s can someone please help me out

And yes Theta=Pi heres the original question, Question 3 here [/URL]