Question

the sum of the first 50 terms of the series 2,6,12,20,30,42... is

Answer 1

a is equal to 2,d is equal to 4,n is equal to 50 Sn is equal to n by 2 into (2a+(n-1)d). An is equal to 50 by2 (2 into 2 +(50-1)4). 25 into (4+196). 25 into 200. answer is equal to 5000