How do I calculate the length of hypotenuse?

Hypot is a mathematical function defined to calculate the length of the hypotenuse of a right-angle triangle. It was designed to avoid errors arising due to limited precision calculations performed on computers.

The Math.hypot(double x, double y) return the sqrt(x2 + y2) without intermediate overflow or underflow. The result will be same with this calculation
Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)).

package org.kodejava.example.math;

public class HypotExample {
    public static void main(String[] args) {
        double number1 = 3.0d;
        double number2 = 5.0d;

        //
        // calculate square root of total value of
        // number1 ^ 2 + number2 ^ 2
        //
        double sqr = Math.hypot(number1, number2);

        System.out.println("Total value= " + (Math.pow(number1, 2) +
                Math.pow(number2, 2)));
        System.out.println("Square root= " + sqr);

    }
}

How do I calculate exponential function?

In mathematics, the exponential function is the function ex, where e is the number (approximately 2.718281828) such that the function ex equals its own derivative. The function f(x) = ex at the point x = 0 is equal to 1.

package org.kodejava.example.math;

public class ExponentExample {

    public static void main(String[] args) {
        double x = 0.0d;

        //
        // calculates e raised to the power of x (e^x)
        //
        double fx = Math.exp(x);

        //
        // calculates e raised to the power of x minus 1 (e^x - 1)
        //
        double fxm1 = Math.expm1(x);

        System.out.println("fx  = " + fx);
        System.out.println("fxm1= " + fxm1);
    }
}

How do I get the exponent of exponential function?

The exponential function is f(x) = ex. The Math.getExponent() method is used to get the x value of the given parameter, in which the parameter is a result of exponential function calculation.

package org.kodejava.example.math;

public class GetExponent {
    public static void main(String[] args) {
        double fx = 1.0d;
        float fx1 = 1.0f;

        int x = Math.getExponent(fx);
        System.out.println("Exponent  = " + x);

        //
        // argument in float
        //
        int xf = Math.getExponent(fx1);
        System.out.println("Exponent1 = " + xf);
    }
}

How do I get signum function of a number?

The code below show you how to get the signum function of a number using the Math.signum() static method call. This method extracts the sign of a real number. If you have a number of x the signum function of x is -1 if x < 0; 0 if x = 0 and 1 if x > 0.

package org.kodejava.example.math;

public class SignumExample {

    public static void main(String[] args) {
        Double zero = 0.0D;
        Double negative = -25.0D;
        Double positive = 15.0D;

        //
        // Get the signum function of value of a number.
        // It returns:
        // * 0 if the value is zero.
        // * 1.0 if value is greater than zero.
        // * -1.0 if value is less than zero.
        //
        double sign1 = Math.signum(zero);
        double sign2 = Math.signum(negative);
        double sign3 = Math.signum(positive);

        //
        // For floating-point value
        //
        float sign4 = Math.signum(zero.floatValue());
        float sign5 = Math.signum(negative.floatValue());
        float sign6 = Math.signum(positive.floatValue());

        System.out.println("In double:");
        System.out.println("Signum of " + zero + " is " + sign1);
        System.out.println("Signum of " + negative + " is " + sign2);
        System.out.println("Signum of " + positive + " is " + sign3);

        System.out.println("In float:");
        System.out.println("Signum of " + zero + " is " + sign4);
        System.out.println("Signum of " + negative + " is " + sign5);
        System.out.println("Signum of " + positive + " is " + sign6);
    }
}

Here is the output of the program:

In double:
Signum of 0.0 is 0.0
Signum of -25.0 is -1.0
Signum of 15.0 is 1.0
In float:
Signum of 0.0 is 0.0
Signum of -25.0 is -1.0
Signum of 15.0 is 1.0

How do I raised a number to the power of n?

The static method Math.pow(double a, double b) can be use to raised the value specified in the a to the power of the value specified in b.

package org.kodejava.example.math;

public class PowerExample {

    public static void main(String[] args) {
        double cubeRoot = 5d;

        //
        // Get the cubed number of cube root
        // x cubed = x^3 (multiplication three times)
        //
        double cubed = Math.pow(cubeRoot, 3);
        System.out.println(cubeRoot + " cubed is " + cubed);
    }
}

Our program print the following output:

5.0 cubed is 125.0