Double Summation Calculator

Define index bounds, step sizes, and optional constraints per index. Parse expressions using i and j with common math functions and constants. See term tables, inner sums, and totals with instant updates after input. Download CSV and PDF for documentation or reports.

Advanced
Supports functions: sin, cos, tan, log, exp, sqrt, abs, min, max, pow.
Use i and j. Radians for trig. '^' allowed for power.
Index i
Index j
Use comparisons (>, <, >=, <=, ==, !=) and &&, ||. Empty means include all.

Result

Computed cells: 9 | i values: 3 | j values: 3

S = Σi=1≤3 Σj=1≤3 f(i,j)
Total sum S = 36.000000
i \ j 1 2 3 Row sum
1 1.000000 2.000000 3.000000 6.000000
2 2.000000 4.000000 6.000000 12.000000
3 3.000000 6.000000 9.000000 18.000000
Column sum 6.000000 12.000000 18.000000 36.000000

Note: Order of summation should match due to Fubini for finite sums.

Formula Used

S = Σi=mn Σj=pq f(i,j), optionally including only terms where C(i,j) is true.
  • Index sets: i ∈ {m, m+Δi, …, n} and j ∈ {p, p+Δj, …, q}.
  • Δi and Δj are step sizes; upper bounds may be inclusive.
  • Supported functions: sin, cos, tan, log, exp, sqrt, abs, min, max, pow.
  • Constants: π via pi, Euler’s number via e.

How to Use

  1. Enter the expression f(i,j) (e.g., i*j - j^2 + sin(i)).
  2. Set ranges and steps for i and j; choose inclusive bounds as needed.
  3. Optionally add a condition like j >= i && (j%2)==0.
  4. Select the summation order and precision; press Compute.
  5. Download the matrix as CSV, or export a PDF report.

Example Data Table

Example for f(i,j)=i*j, i=1..3, j=1..3, step=1, inclusive bounds.

i \ j123Row sum
11236
224612
336918
Column sum6121836

FAQs

Arithmetic +, −, ×, ÷, %, power (^), comparisons, logical &&, ||, and functions sin, cos, tan, asin, acos, atan, log, exp, sqrt, abs, min, max, pow.

Each index has a toggle for including the upper bound. Lower bounds are always included.

Radians. Convert degrees with sin(x*pi/180) or similar where needed.

For finite sums with the same included terms, order independence holds; both orders sum the identical set of terms.

For stability, the calculator limits to 10,000 cells. Reduce ranges or increase steps if you reach the limit.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.