Find S20 for the series -1 + -3 + -5 + -7 +…
Solution:-
a1 = -1, d = -2
S20 = 
[2*a1 + (n-1)*d]
S20 = 
[2*(-1) + (20-1)*-2]
S20 = – 400
Recent Posts
Recent Comments
- Sir Sagar on Problem 1073
- Hugh Janus on Problem 1073
- Bailey on Problem 1017
- Christopher Mace Bingham on Problem 1154
- Chris on Problem 174