import java.lang.Math. ;

The java.lang.Math class is a part of the java.lang package, which is automatically imported in all Java programs. This means that you do not need to import the Math class explicitly in your code.

You can use the Math class to perform various mathematical operations and functions, such as trigonometric functions, logarithms, and random number generation. Here is an example of using the Math.sin method to calculate the sine of an angle:

double x = Math.toRadians(30);  // convert degrees to radians
double y = Math.sin(x);
System.out.println(y);  // prints 0.5

Here is an example of using the Math.random method to generate a random number between 0 and 1:

double x = Math.random();
System.out.println(x);  // prints a random number between 0 and 1

You can also use the Math class to perform basic arithmetic operations, such as addition, subtraction, multiplication, and division. Here is an example of using the Math.max method to find the maximum of two numbers:

int x = 5;
int y = 3;
int z = Math.max(x, y);
System.out.println(z);  // prints 5