please help me to solve it with explanation.

3. Use the fact that the power series expression, 1 1 - x = En=ox, has radius of convergence R = 1 to: a) Find the power series representation and radius of convergence for the function x 3 f ( x ) = - x4+ 16 b) Find the power series representation for the function f(x) = In(x4+ 16). 4. Let C be the parametric curve x = cos(at) + sin(at) and y = cos(at) - sin(at) + 2, where a > 0 is a constant and 0 S t 0 is a constant