4. Find the sum of each series by associating it with some known Maclaurin series. 2 π a. 1- 元 4 πο 6 + 2! 4! 4 8 b. 2+ + + - 16 2! 3! 4! 6! +... + (Be careful here. This series doesn't exactly match up with a known Macluarin series, but it is very close.)