Write down the cartesian equation of the tangent + normal to the following parabolas at the points indicated.
(a) x = cos 2t, y = cos t at the point where t = PI/4
(b) x = t + 2, y = t^2/4 + 1 at the vertex.
For (a), I keep on getting 2x - 4sqrt(2) + 4 = 0 and 4x + sqrt(2)y -1 = 0 for the tangent and the normal respectively, which is wrong.
For (b), I have no clue how to do it.
Could someone please help me?