Helo please help with this question Find the sum of the firs

Helo, please help with this question.

Find the sum of the first 20 terms of the sequence 5, 9, 13, …

Solution

Dear Student Thank you for using Chegg Given a sequence 5,9,13 ….. So clearly difference between consequent terms is same i.e. 9-5 = 4 & 13-9 = 4 Hence since the difference between cosequent terms is same s the gven sequence is an AP Sum of n terems of AP is given by Sn = (n/2)*(2a + (n-1)d) For given sequence a = 5 d = 4 n = 20 S20 = (20/2)*(2*5+ (20-1)*4) = 860 Hence Solved