Hello
We just put n = 20 in Sn
Given Sn = 2n2 + 5n
Putting n = 20
S20 = 2(20)2 + 5(20)
S20 = 2(400) + 100
S20 = 800 + 100
S20 = 900
Written on Oct. 30, 2017, 9:44 p.m.
-
Answer of this question
If sum of first n terms of an AP 2n^2 + 5n. Then find S20
Davneet Singh
Comment