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Integral Calculator

Find indefinite and definite integrals of functions of x, with an antiderivative, fundamental-theorem steps, numerical verification, and graph.

Indefinite integral

ExampleSample values — edit any field to see your result.

Indefinite integral

-cos(x)+0.3333333333333333*x^3 + C

Estimated result

Result note
Differentiate this result to recover the integrand.

Integrand

-4-2024-10-50510xyy = sin(x)+x^2

Integration result

StepExpression
Integrandsin(x)+x^2
Antiderivative-cos(x)+0.3333333333333333*x^3
Constant+ C

Find an indefinite antiderivative or evaluate a definite integral between two bounds. Results include a simplified symbolic expression, an independent numeric check for definite integrals, and a graph of the function over the interval.

Formula

The Fundamental Theorem of Calculus connects antiderivatives and definite integrals:

if F′(x) = f(x), then ∫[a,b] f(x) dx = F(b) − F(a)

An indefinite result includes + C because all functions differing by a constant have the same derivative.

Examples

Integrate x²

The indefinite integral of x² is x³/3 + C. From 0 to 3, its definite integral is 9.

Integrate sin(x)

An antiderivative of sin(x) is −cos(x). From 0 to π, the definite integral is 2.

A negative definite result represents net signed area. Use the graph to see where the function lies above or below the x-axis.

Frequently asked questions

What is an indefinite integral?
It is a family of antiderivatives written with an arbitrary constant, commonly shown as + C.
What is a definite integral?
It is the signed accumulation of a function between lower and upper bounds, computed with the Fundamental Theorem of Calculus when an antiderivative exists.
Does a definite integral always equal geometric area?
No. Regions below the x-axis count negatively. Total geometric area requires splitting the interval at zeros and adding absolute areas.
How is the numeric check calculated?
The calculator uses composite Simpson integration as an independent numerical check of the symbolic definite result.

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