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Midpoint Rule Supplied Curvature Bound Tool

Compute midpoint rule supplied curvature bound from explicit bounded inputs.

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Description

Return a composite-midpoint quadrature error bound.

A truncation term and a rigorous error bound require different information. Taylor and quadrature bounds need derivative bounds over the entire relevant interval; a derivative sampled at one point or a leading asymptotic term does not automatically control the full approximation error.

Return a composite-midpoint quadrature error bound.

When to use this tool

Use Midpoint Rule Supplied Curvature Bound when checking the stated approximation term or derivative-bound calculation.

How to use the tool and how it works

  1. Enter lower, upper, curvatureBound, panels. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read errorBound. Use the output convention below.

Return a composite-midpoint quadrature error bound. Require upper >= lower, curvatureBound >= 0 and panels 1..1000000; errorBound = M*(upper-lower)³/(24*panels²).1

The composite midpoint error bound uses an interval-wide bound on the absolute second derivative, with cubic interval-length and inverse-square panel-count scaling.2

Input fieldMeaning and unitsAccepted input
lowerLowerRequired. Finite number.
upperUpperRequired. Finite number.
curvatureBoundInterval-wide bound on absolute second derivative, not geometric curvature.Required. Finite number.
panelsPanelsRequired. Safe integer; minimum 1; maximum 1000000.
Output fieldInterpretationReturned shape
errorBoundError BoundRequired. Finite number.
json
{
  "input": {
    "lower": 0,
    "upper": 2,
    "curvatureBound": 3,
    "panels": 1
  },
  "output": {
    "errorBound": 1
  }
}

Limitations and assumptions

  • M must bound abs(f'') over the interval; it is a second-derivative bound rather than geometric curvature, and no integrand is inspected.
  • Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
  • Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Establish the required smoothness and interval-wide bounds for a rigorous estimate; analyze the complete numerical approximation when only local derivative data are available.

References

  1. Calculation and input contract: calculus/midpoint-rule-supplied-curvature-bound — tool.io

  2. Numerical integration — OpenStax

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