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Find determinant of a matrix in Java Programming

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In this section, you will learn how to determine the determinant of 2x2 matrix.

Find determinant of a matrix in Java Programming

A determinant is a real number associated with every square matrix or, you can say it is a rectangular array of numbers where the number of rows and columns are equal.It is a scale factor for measure when the matrix is regarded as a linear transformation. Here we are going to find the determinant of 2x2 matrix.

In 22 matrix,
a[0][0] a[0][1]
a[1][0] a[1][1]
determinant = a[0][0] * a[1][1] - a[0][1] * a[1][0];

Here is the code:

public class Determinant {
	public int determinant(int[][] arr) {
		int result = 0;
		if (arr.length == 1) {
			result = arr[0][0];
			return result;
		}
		if (arr.length == 2) {
			result = arr[0][0] * arr[1][1] - arr[0][1] * arr[1][0];
			return result;
		}
		for (int i = 0; i < arr[0].length; i++) {
			int temp[][] = new int[arr.length - 1][arr[0].length - 1];

			for (int j = 1; j < arr.length; j++) {
				for (int k = 0; k < arr[0].length; k++) {

					if (k < i) {
						temp[j - 1][k] = arr[j][k];
					} else if (k > i) {
						temp[j - 1][k - 1] = arr[j][k];
					}
				}
			}
			result += arr[0][i] * Math.pow(-1, (int) i) * determinant(temp);
		}
		return result;
	}

	public static void main(String[] args) {
		int array[][] = { { 5, 6 }, { 8, 9 } };
		Determinant d = new Determinant();
		int result = d.determinant(array);
		System.out.println(result);
	}
}

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