The trapezoidal rule method is one of the simplest methods to find the area under an arbitrary function. In this method, the area under the function is divided into n sections. Then the total area is approximated by the summation of the areas of trapezoids.

The area of a trapezoid can be found by the following relation:

where h is the length of each section. The total area uder the curve is approximated by the summation of all trapezoids’ areas.