How would I solve the following problem? What is the sum of the first eight terms of a geometric sequence whose common ratio is 1/2? Thank you in advance for your help.

Question

asked Dec 20, 2019 60.7k views

1 Answer

Julien Grenier · Answer 1 · 2019-12-25T23:29:15+0000

You would need to know the first term or two other terms of the sequence.

You can use the formula:

Sn = (a1(r^n - 1)) / (1 - r)

Where a1 is the first term and r is the common ratio