Java Chord Method

Implementation of Chord Method written in Java.

IN
-3
0
0.00001
OUT
: -1.0 f(x): -2.0
X: -2.0 f(x): -1.0
X: -2.3333333333333335 f(x): -0.22222222222222188
X: -2.4 f(x): -0.04000000000000026
X: -2.4117647058823533 f(x): -0.006920415224912602
X: -2.413793103448276 f(x): -0.0011890606420928984
X: -2.4141414141414144 f(x): -2.0406081012080968E-4
X: -2.414201183431953 f(x): -3.501277966366789E-5

import java.util.Scanner;

// ? 2018 TheFlyingKeyboard and released under MIT License
// theflyingkeyboard.net
public class Main {
    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);
        double intervalBegin;
        double intervalEnd;
        double x;
        double precision;

        System.out.print("Enter begining of interval: ");
        intervalBegin = reader.nextDouble();

        System.out.print("Enter end of interval: ");
        intervalEnd = reader.nextDouble();

        System.out.print("Enter precision of method: ");
        precision = reader.nextDouble();

        if(function(intervalBegin) * function(intervalEnd) > 0.0d){
            System.out.println("Function has same signs at ends of interval");
            return;
        }

        x = (intervalBegin * function(intervalEnd) - intervalEnd * function(intervalBegin)) / (function(intervalEnd) - function(intervalBegin));

        while(Math.abs(function(x)) > precision){
            System.out.println("X: " + x + " f(x): " + function(x));

            if(function(intervalBegin) * function(x) < 0){
                x = (x * function(intervalBegin) - intervalBegin * function(x)) / (function(intervalBegin) - function(x));
            }else{
                x = (x * function(intervalEnd) - intervalEnd * function(x)) / (function(intervalEnd) - function(x));
            }
        }
    }

    static double function(double x) { //x^2 + 2x -1
        return x * (x + 2) - 1;
    }
}