Integral Calculator
Worked example
Step-by-step solution
Step 1 / 4
Choose u and dv
u = x gets simpler when differentiated; e^x is easy to integrate.
Step 2 / 4
Apply integration by parts
Use ∫u dv = uv − ∫v du.
Step 3 / 4
Integrate the remaining term
Add the constant of integration.
Step 4 / 4
Check by differentiating
The derivative of xe^x − e^x is e^x + xe^x − e^x = xe^x.
Answer
e^x(x − 1) + C
How to use the Integral Calculator
Enter an integral and this integral calculator names the technique it uses, works through every substitution, and checks the antiderivative by differentiating it back.
- Type the integral, for example “integral of x e^x dx”, or give bounds for a definite integral.
- Press Solve it. The calculator picks a technique: basic rules, u-substitution, integration by parts or partial fractions.
- Follow the substitution in each step and the + C on indefinite integrals.
- The last step differentiates the answer to confirm it.
Choosing an integration technique
Start with the basic rules. If the integrand contains a function and its derivative, try u-substitution. If it is a product of two different kinds of functions, such as a polynomial times an exponential, integration by parts usually works.
For integration by parts, choose u to be the factor that gets simpler when differentiated. In ∫ x e^x dx, u = x becomes 1 while e^x stays easy to integrate.
Frequently asked questions
Can it evaluate definite integrals?
Yes. Give the bounds, for example “integral from 0 to 1 of x² dx”, and it finds the antiderivative and evaluates it exactly: 1/3.
Why is there a + C in the answer?
An indefinite integral is a family of antiderivatives that differ by a constant, because the derivative of any constant is zero.
What if an integral has no elementary antiderivative?
Some integrals, such as ∫ e^(−x²) dx, cannot be written with elementary functions. The calculator says so and, for definite integrals, gives a numerical value.
Related calculators
Have a different kind of math problem? Try the free math solver. Use the subject menu for physics and chemistry.