r = -5
r = 5
You can tell what a is, and now
Sn = a(r^n - 1)/(r-1)
so just plug in your numbers
evaluate each geometric series described
21) -3 + 15 - 75 + 375..., n=6
22) 1 + 5 + 25 + 125..., n=8
1 answer
21) -3 + 15 - 75 + 375..., n=6
22) 1 + 5 + 25 + 125..., n=8
1 answer
3 answers
2 answers
0 answers
1 answer