How to find number of terms in a geometric progression

Question

What is the equation two find the number of terms in the geometric progression given first two and the last term?

you need $|a_2/a_1|\neq 1$ – Asinomás Oct 04 '17 at 18:25 — Asinomás, Oct 04 '17 at 18:25

score 0 · Accepted Answer · answered Oct 04 '17 at 18:24

0

Let $a_1,a_2$ be the first two terms and let $a_f$ be the final term, then the number of terms is $\log_{|a_2/a_1|}(|a_f/a_1|)+1$.

answered Oct 04 '17 at 18:24

Asinomás

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