Example 1: Integral of exp(2x)

The integral \int_1^3 e^{2x} \, dx is computed and compared to its expected value. 

import com.imsl.math.*;

public class QuadratureEx1 {

    public static void main(String args[]) {
        Quadrature.Function fcn = new Quadrature.Function() {
            public double f(double x) {
                return Math.exp(2.0 * x);
            }
        };

        Quadrature q = new Quadrature();
        double result = q.eval(fcn, 1.0, 3.0);

        double expect = (Math.exp(6) - Math.exp(2)) / 2.0;
        System.out.println("result = " + result);
        System.out.println("expect = " + expect);
    }
}

Output

result = 198.01986869690225
expect = 198.01986869690222
Link to Java source.