Java has had several advanced usage application including working with complex calculations in physics, architecture/designing of structures, working with Maps and corresponding latitudes/longitudes, etc.

In this Java tutorial, you will learn:

All such applications require using complex calculations/equations that are tedious to perform manually. Programmatically, such calculations would involve usage of logarithms, trigonometry, exponential equations, etc.

Java Math Class Tutorial

Now, you cannot have all the log or trigonometry tables hard-coded somewhere in your application or data. The data would be enormous and complex to maintain.

Java provides a very useful class for this purpose. It is the Math java class (java.lang.Math).

This class provides methods for performing the operations like exponential, logarithm, roots and trigonometric equations too.

Let us have a look at the methods provided by the Java Math class.

The two most fundamental elements in Math are the 'e' (base of the natural logarithm) and 'pi' (ratio of the circumference of a circle to its diameter). These two constants are often required in the above calculations/operations.

Hence the Math class java provides these two constants as double fields.

Math.E - having a value as 2.718281828459045

Math.PI - having a value as 3.141592653589793

A) Let us have a look at the table below that shows us the Basic methods and its description

Method Description Arguments
abs Returns the absolute value of the argument Double, float, int, long
round Returns the closed int or long (as per the argument) double or float
ceil Math ceil function in Java returns the smallest integer that is greater than or equal to the argument Double
floor Java floor method returns the largest integer that is less than or equal to the argument Double
min Returns the smallest of the two arguments Double, float, int, long
max Returns the largest of the two arguments Double, float, int, long

Below is the code implementation of the above methods:

Note: There is no need to explicitly import java.lang.Math as its imported implicitly. All its methods are static.

Integer Variable

int i1 = 27;
int i2 = -45;

Double(decimal) variables

double d1 = 84.6;
double d2 = 0.45;

Java Math abs() method with Example

Java Math abs() method returns the absolute value of the argument.

public class Guru99 {
 public static void main(String args[]) {

  int i1 = 27;
  int i2 = -45;
  double d1 = 84.6;
  double d2 = 0.45;
  System.out.println("Absolute value of i1: " + Math.abs(i1));

  System.out.println("Absolute value of i2: " + Math.abs(i2));

  System.out.println("Absolute value of d1: " + Math.abs(d1));

  System.out.println("Absolute value of d2: " + Math.abs(d2));

 }
}
Output:
Absolute value of i1: 27
Absolute value of i2: 45
Absolute value of d1: 84.6
Absolute value of d2: 0.45

Java Math.round() method with Example

Math.round() method in Java returns the closed int or long as per the argument. Below is the example of math.round Java method.

public class Guru99 {
 public static void main(String args[]) {
  double d1 = 84.6;
  double d2 = 0.45;
  System.out.println("Round off for d1: " + Math.round(d1));

  System.out.println("Round off for d2: " + Math.round(d2));
 }
}

Output:
Round off for d1: 85
Round off for d2: 0

Java Math.ceil and Math.floor method with Example

The Math.ceil and Math.floor in Java methods are used to return the smallest and largest integer that are greater than or equal to the argument. Below is the Math floor and ceiling Java example.

public class Guru99 {
 public static void main(String args[]) {
  double d1 = 84.6;
  double d2 = 0.45;
  System.out.println("Ceiling of '" + d1 + "' = " + Math.ceil(d1));

  System.out.println("Floor of '" + d1 + "' = " + Math.floor(d1));

  System.out.println("Ceiling of '" + d2 + "' = " + Math.ceil(d2));

  System.out.println("Floor of '" + d2 + "' = " + Math.floor(d2));

 }
}

We will get the below output of the math.ceil in Java example.

Output:

Ceiling of '84.6' = 85.0
Floor of '84.6' = 84.0
Ceiling of '0.45' = 1.0
Floor of '0.45' = 0.0

Java Math.min() method with Example

The Java Math.min() method returns the smallest of the two arguments.

public class Guru99 {
 public static void main(String args[]) {
  int i1 = 27;
  int i2 = -45;
  double d1 = 84.6;
  double d2 = 0.45;
  System.out.println("Minimum out of '" + i1 + "' and '" + i2 + "' = " + Math.min(i1, i2));

  System.out.println("Maximum out of '" + i1 + "' and '" + i2 + "' = " + Math.max(i1, i2));

  System.out.println("Minimum out of '" + d1 + "' and '" + d2 + "' = " + Math.min(d1, d2));

  System.out.println("Maximum out of '" + d1 + "' and '" + d2 + "' = " + Math.max(d1, d2));

 }
}
Output:
Minimum out of '27' and '-45' = -45
Maximum out of '27' and '-45' = 27
Minimum out of '84.6' and '0.45' = 0.45
Maximum out of '84.6' and '0.45' = 84.6

B) Let us have a look at the table below that shows us the Exponential and Logarithmic methods and its description-

Method Description Arguments
exp Returns the base of natural log (e) to the power of argument Double
Log Returns the natural log of the argument double
Pow Takes 2 arguments as input and returns the value of the first argument raised to the power of the second argument Double
floor Java math floor returns the largest integer that is less than or equal to the argument Double
Sqrt Returns the square root of the argument Double

Below is the code implementation of the above methods: (The same variables are used as above)

public class Guru99 {
 public static void main(String args[]) {
  double d1 = 84.6;
  double d2 = 0.45;
  System.out.println("exp(" + d2 + ") = " + Math.exp(d2));

  System.out.println("log(" + d2 + ") = " + Math.log(d2));

  System.out.println("pow(5, 3) = " + Math.pow(5.0, 3.0));

  System.out.println("sqrt(16) = " + Math.sqrt(16));

 }
}
Output:
exp(0.45) = 1.568312185490169
log(0.45) = -0.7985076962177716
pow(5, 3) = 125.0
sqrt(16) = 4.0

C) Let us have a look at the table below that shows us the Trigonometric methods and its description-

Method Description Arguments
Sin Returns the Sine of the specified argument Double
Cos Returns the Cosine of the specified argument double
Tan Returns the Tangent of the specified argument Double
Atan2 Converts rectangular coordinates (x, y) to polar(r, theta) and returns theta Double
toDegrees Converts the arguments to degrees Double
Sqrt Returns the square root of the argument Double
toRadians Converts the arguments to radians Double

Default Arguments are in Radians

Below is the code implementation:

public class Guru99 {
 public static void main(String args[]) {
  double angle_30 = 30.0;
  double radian_30 = Math.toRadians(angle_30);

  System.out.println("sin(30) = " + Math.sin(radian_30));

  System.out.println("cos(30) = " + Math.cos(radian_30));

  System.out.println("tan(30) = " + Math.tan(radian_30));

  System.out.println("Theta = " + Math.atan2(4, 2));

 }
}
Output:
sin(30) = 0.49999999999999994
cos(30) = 0.8660254037844387
tan(30) = 0.5773502691896257
Theta = 1.1071487177940904

Now, with the above, you can also design your own scientific calculator in java.