Algebra & Equations
Geometric Series Sum
Sum of the first n geometric terms.
Formula
Formula
Sn = a11 − rn1 − r
Variables
| Symbol | Definition | Type & range | Units | Role |
|---|---|---|---|---|
| a₁ | first term | computed result | — | result |
| r | common ratio | real number (ℝ) | — | input |
| n | number of terms | integer (ℤ) | — | input |
Try it yourself
Interactive calculator
Worked examples
Example 1
Givenfirst term a₁ = 1, ratio r = 2, n = 10
Result1023
Example 2
Givenfirst term a₁ = 3, ratio r = 0.5, n = 4
Result5.625