Geometric Sequence Calculator

Find the nth term and sum of a geometric sequence.

nth term 384
Sum of first n 765

Formula: aₙ = a₁ r^(n−1) ; Sₙ = a₁(1−rⁿ)/(1−r)

Step-by-step with your numbers:
1. Values used:
2. First term = 3
3. Common ratio = 2
4. Term number (n) = 8
5.
6. nth term = 384
7. Sum of first n = 765
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A sequence where each term is multiplied by a fixed ratio.

The math behind it

nth term = a₁ × r^(n−1). Sum = a₁(1 − rⁿ) ÷ (1 − r) when r ≠ 1.

Worked example

3, 6, 12, … 8th term = 384, sum = 765.

FAQ

|r| < 1?

The infinite sum converges to a₁ ÷ (1 − r).