Author: Oscar Cronquist Article last updated on May 05, 2022

The SERIESSUM function calculates the sum of a power series based on the following formula:

SERIESSUM(x, n, m, a) = a1*x^n + a2*x^(n+m)+ai*x^(n+(i-1)*m)

This allows you to approximate a mathematical function by a power series expansion.

Formula in cell C3:


An approximation to the cosine of Pi/4 radians, or 45 degrees (0.707103).

Excel Function Syntax

SERIESSUM(x, n, m, coefficients)


x Required. The input value to the power series.
n Required. The initial power to which you want to raise x.
m Required. The step by which to increase n for each term in the series.
coefficients Required. A set of coefficients by which each successive power of x is multiplied. The number of values in coefficients determines the number of terms in the power series. For example, if there are three values in coefficients, then there will be three terms in the power series.