For the geometric progression with first term 2 and common ratio −0.4, answer the following.
a. (a) Calculate the remainder after the first five terms.
b. (b) Determine whether the first five terms give the sum correct to within 1% of the sum to infinity.
c. (c) Find the least value of n for which the sum of the first n terms is accurate to within 1% of the sum to infinity.