2. Solve the following individual problems. You must show your work to get full credits. (a) Find the power series representation centered at the origin of the function f(:1:) = 2 cos2(:r) Hint: use double angle formula to rewrite f (J) rst. (b) The parametric: equation of a astmid is the following :1: = 2.3033(6) ,y = 2 3119(9). Write down an integral that computes the arelength of the astroid. You don't need to evaluate the integral. Figure 1: plot of the astroid