Integral Approximation Calculator

Use this tool to find the approximate area from a curve to the x axis.
Read Integral Approximations to learn more.

Note: use your eyes and common sense when using this! Some curves don't work well, for example tan(x), 1/x near 0, and functions with sharp changes give bad results.

Plus and Minus

definite integral cos(x) from 1 to 3

When the curve is below the axis the value of the integral is negative!

So we get a "net" value.

Total Area

If we want a total area (say we wanted to paint it) we can use the absolute value function abs(). Or we can manually find where the curve crosses the axis and then work out separate integrals and reverse the negatives before adding.