Math & Trig
SERIESSUM Function in Excel
Returns the sum of a power series based on the formula.
Syntax
- =SERIESSUM(x, n, m, coefficients)
Arguments
- x (required): Input value
- n (required): Initial power
- m (required): Step for each term
- coefficients (required): Array of coefficients
Examples
- =SERIESSUM(PI()/4, 0, 2, {1, -1/2, 1/24}) - Cosine approximation - Result: 0.707
SERIESSUM in reporting workflows
- Use absolute references when copying formulas across rows.
- For conditional totals see [SUMIF](/functions/sumif/) and [SUMIFS](/functions/sumifs/).
- Filtered lists may need [SUBTOTAL](/functions/subtotal/) instead of SUM on visible cells only.
Common errors
- Coefficients must be array
Use cases
- Taylor series
- Mathematical modeling
- Engineering
Frequently asked questions
- What is SERIESSUM used for? SERIESSUM calculates power series: Σ(coefficient × x^(n+i×m)). It's used for Taylor series approximations, polynomial evaluation, and mathematical modeling. Essential for engineering and scientific calculations.
- How do I approximate sin(x) using SERIESSUM? Sin Taylor series: x - x³/3! + x⁵/5! - ... Use =SERIESSUM(x, 1, 2, {1, -1/6, 1/120, -1/5040}). Parameters: x=angle in radians, n=1 (first power), m=2 (powers increase by 2), coefficients from Taylor expansion.
- How do I set up the coefficients array? Coefficients are the multipliers for each term. For series a₀ + a₁x² + a₂x⁴: coefficients={a₀, a₁, a₂}. The formula applies: a₀×x^n + a₁×x^(n+m) + a₂×x^(n+2m). Calculate coefficients from your series formula.
Editorial review
- Reviewed by Excel.Directory Editorial Team. Updated May 2026.