In mathematics, and more specifically in numerical analysis, the trapezoidal rule (also known as the trapezoid rule or trapezium rule) is a technique for approximating the definite integral. . The trapezoidal rule works by approximating the region under the graph of the function as a trapezoid and calculating its area. 

Use multiple-segment Simpson’s 1/3 rule of integration to solve integrals, and derive the true error formula for multiple-segment Simpson’s 1/3 rule. The trapezoidal rule was based on approximating the integrand by a first order polynomial, and then integrating the polynomial over interval of integration.