Implementation of Trapezoidal Rule (Integral Approximation) written in Java.
Enter beginning of interval: -2 Enter end of interval: 2 Enter number of iterations: 1000000 Integral is equal to: 5.333349333344088
import java.util.Scanner; // ? 2018 TheFlyingKeyboard and released under MIT License // theflyingkeyboard.net public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); double intervalBegin; double intervalEnd; int iterations; double integral; double step; System.out.print("Enter beginning of interval: "); intervalBegin = scanner.nextDouble(); System.out.print("Enter end of interval: "); intervalEnd = scanner.nextDouble(); System.out.print("Enter number of iterations: "); iterations = scanner.nextInt(); step = (intervalEnd - intervalBegin) / iterations; integral = 0.5 * (function(intervalBegin) + function(intervalEnd)); for (int i = 0; i < iterations; ++i) { integral += function(intervalBegin + step * i); } integral *= step; System.out.println("Integral is equal to: " + integral); } private static double function(double x) { return x * x; } }
Java Trapezoidal Rule