How this calculation works
If the arithmetic step is zero, the weights form an ordinary finite geometric series multiplied by the first term.
THE FORMULA
S = Σ(a + kd) rᵏ for k = 0,…,n−1A worked example
1 + 2/2 + 3/4 + 4/8 = 3.25.
Good to know
The first term has geometric weight 1.
Reference: OpenStax Algebra and Trigonometry (opens in a new tab) ↗
Read the result
Add a finite series whose arithmetic term is weighted by a geometric multiplier.
The primary result is labeled “Finite sum”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
The first term has geometric weight 1.
For a related exercise, try the quadratic equation solver.
A few questions, answered
How can I check the default inputs by hand?
1 + 2/2 + 3/4 + 4/8 = 3.25.
Which rule does this calculator apply?
S = Σ(a + kd) rᵏ for k = 0,…,n−1