x̄ - > Mathematical problem using Java

Solving a mathematical problem using Java. Let's consider finding the factorial of a given number N:

```java

import java.math.BigInteger;

public class Factorial {

    public static BigInteger factorial(int N) {

        BigInteger result = BigInteger.ONE;

        

        for (int i = 1; i <= N; i++) {

            result = result.multiply(BigInteger.valueOf(i));

        }

        

        return result;

    }

    public static void main(String[] args) {

        int N = 10;

        BigInteger factorialN = factorial(N);

        System.out.println("Factorial of " + N + " is: " + factorialN);

    }

}

```

In this example, we use the `BigInteger` class from the `java.math` package to handle large numbers since factorials can grow rapidly. The `factorial` method takes an integer `N` as input and calculates the factorial using a loop. Finally, the `main` method demonstrates how to use the `factorial` method by calculating the factorial of 10 and printing the result.

This code will output:

```

Factorial of 10 is: 3628800

```

Note that the `BigInteger` class allows you to perform arithmetic operations on integers of any size, which is necessary when dealing with factorials of large numbers.