Find the partial sum S_50 for sequence defines recursively as a_n + 1 = a_n + 3 and a_1 = 1 Find the partial sum S_50 for sequence defined recursively as a_n + 1 = 2a_n and a_1 = 1 Let {a_n} be an arithmetic sequence with a_1 = 1 and d = 2 ind the 100^th term, a_100)