Java Secant Method

Implementation of Secant Method written in Java.

IN
-3
-1
0.0000001
OUT
X: -3.0 f(x): 2.0
X: -2.0 f(x): -1.0
X: -3.0 f(x): 2.0
X: -2.3333333333333335 f(x): -0.22222222222222188
X: -2.4 f(x): -0.04000000000000026
X: -2.4146341463414633 f(x): 0.0011897679952406204
X: -2.41421143847487 f(x): -6.007286838749515E-6

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 xn1; //x_(n - 1)
        double xn; //x_n
        double x;
        double precision;

        System.out.print("Enter begining of interval: ");
        xn1 = reader.nextDouble();

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

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

        if (function(xn1) * function(xn) > 0.0d) {
            System.out.println("Function has same signs at ends of interval");
            return;
        }

        x = xn1;

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

            x = xn - ((function(xn) * (xn - xn1)) / (function(xn) - function(xn1)));
            xn1 = xn;
            xn = x;
        }

    }

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