import java.util.function.Function;
public class integralCalc
{
   public static void main(String[] args)
   {
      double a = 0;
      double b = 3;
      double n = 1000000;
      double increment = ((b - a) / n);
      Function<Double, Double> myFunc = c -> (Math.exp(c) * Math.pow(c, 2));
      double result = 0.0;
      for (double i = 1.0; i <= 1000000; i++)
      {
         result += ((myFunc.apply(i * increment) + myFunc.apply(increment * i - increment)) * (increment / 2));
      }
      System.out.println("Integral Approximation for function: " + result);
   }
}