Introduction to Java Math: Features and Examples

답변:

Java Math is a part of the Java Standard Library that provides a collection of methods and constants for performing mathematical operations. The java.lang.Math class includes methods for basic arithmetic, trigonometric functions, logarithms, exponentiation, and more. It is a final class, which means it cannot be subclassed, and all its methods are static, allowing you to call them without creating an instance of the class.

Key Features of Java Math

Basic Arithmetic Operations: Methods for addition, subtraction, multiplication, and division.
Trigonometric Functions: Methods for sine, cosine, tangent, and their inverses.
Exponential and Logarithmic Functions: Methods for calculating powers and logarithms.
Rounding Functions: Methods for rounding numbers to the nearest integer.
Constants: Predefined constants like Math.PI and Math.E.

Commonly Used Methods

Here are some commonly used methods in the Math class:

Math.abs(double a): Returns the absolute value of a number.
Math.sqrt(double a): Returns the square root of a number.
Math.pow(double a, double b): Returns the value of a raised to the power of b.
Math.max(double a, double b): Returns the greater of two values.
Math.min(double a, double b): Returns the smaller of two values.
Math.random(): Returns a random double value between 0.0 and 1.0.
Math.sin(double a), Math.cos(double a), Math.tan(double a): Trigonometric functions.
Math.log(double a): Returns the natural logarithm (base e) of a number.
Math.exp(double a): Returns Euler's number raised to the power of a.

Examples

Here are some examples demonstrating the use of the Math class in Java:

public class MathExample {
    public static void main(String[] args) {
        // Absolute value
        double number = -10.5;
        System.out.println("Absolute value of " + number + " is: " + Math.abs(number));

        // Square root
        double square = 16.0;
        System.out.println("Square root of " + square + " is: " + Math.sqrt(square));

        // Power
        double base = 2.0;
        double exponent = 3.0;
        System.out.println(base + " raised to the power of " + exponent + " is: " + Math.pow(base, exponent));

        // Maximum and Minimum
        double a = 5.0;
        double b = 10.0;
        System.out.println("Maximum of " + a + " and " + b + " is: " + Math.max(a, b));
        System.out.println("Minimum of " + a + " and " + b + " is: " + Math.min(a, b));

        // Random number
        System.out.println("Random number: " + Math.random());

        // Trigonometric functions
        double angle = Math.toRadians(30); // Convert degrees to radians
        System.out.println("Sine of 30 degrees: " + Math.sin(angle));
        System.out.println("Cosine of 30 degrees: " + Math.cos(angle));
        System.out.println("Tangent of 30 degrees: " + Math.tan(angle));

        // Logarithm
        double value = 10.0;
        System.out.println("Natural logarithm of " + value + " is: " + Math.log(value));

        // Exponential
        double exponentValue = 2.0;
        System.out.println("e raised to the power of " + exponentValue + " is: " + Math.exp(exponentValue));
    }
}

Output

When you run the above code, you will see output similar to the following:

Absolute value of -10.5 is: 10.5
Square root of 16.0 is: 4.0
2.0 raised to the power of 3.0 is: 8.0
Maximum of 5.0 and 10.0 is: 10.0
Minimum of 5.0 and 10.0 is: 5.0
Random number: 0.123456789 (example output)
Sine of 30 degrees: 0.49999999999999994
Cosine of 30 degrees: 0.8660254037844387
Tangent of 30 degrees: 0.5773502691896257
Natural logarithm of 10.0 is: 2.302585092994046
e raised to the power of 2.0 is: 7.38905609893065

Conclusion