Numerical Integration Calculator

Free online numerical integration calculator. Compare Trapezoidal, Simpson's 1/3, and Simpson's 3/8 rules with interval tables and area plots.

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How to Use Numerical Integration Calculator

  1. Enter the function and upper/lower definite limits.
  2. Set the desired number of intervals (subdivisions).
  3. Select the rule: Trapezoidal, Simpson's 1/3, or Simpson's 3/8.
  4. Compare approximation accuracy, inspect weights, and export interval data.

Approximating Area Under Curves

Numerical integration approximates definite integrals by dividing the area into geometric panels (trapezoids or parabolas) and summing their weights.

Frequently Asked Questions

What are the interval requirements for Simpson's rules?
Simpson's 1/3 rule requires an even number of intervals (n), while Simpson's 3/8 rule requires n to be a multiple of 3.