Find the sum of −59, −41, 73, −92, 81, −(−41) and −3.
Find the sum of two middle terms of hte A.P.: −43,−1,−23,−13,...,413
Find the sum f two middle most terms of the AP−43,−1,−23,...,413
Find the sum of the series s = 1 + 12(1 + 2) + 13(1 + 2 + 3) + 14(1 + 2 + 3 + 4) + .........upto 40 terms.