Finding the matrix cosine.

Here’s an example of a Java problem that demonstrates how to find the cosine of a matrix:

 import java.util.Arrays;

  public class MatrixCosine {

    public static void main(String[] args) {

        double[][] matrix = {

            {1.0, 2.0, 3.0},

            {4.0, 5.0, 6.0},

            {7.0, 8.0, 9.0}

        };

        double[][] cosineMatrix = findMatrixCosine(matrix);

        System.out.println("Original Matrix:");

        printMatrix(matrix);

        System.out.println("Cosine Matrix:");

        printMatrix(cosineMatrix);

    }
    public static double[][] findMatrixCosine(double[][] matrix) {

        int rows = matrix.length;

        int cols = matrix[0].length;

        double[][] cosineMatrix = new double[rows][cols];

        for (int i = 0; i < rows; i++) {

            for (int j = 0; j < cols; j++) {

                cosineMatrix[i][j] = Math.cos(matrix[i][j]);

            }
        }
        return cosineMatrix;
    }

    public static void printMatrix(double[][] matrix) {

        for (double[] row : matrix) {

            System.out.println(Arrays.toString(row));

        }

        System.out.println();

    }

}

In this example, we have a 2D array `matrix` representing a matrix of values. The `findMatrixCosine` method calculates the cosine of each element in the matrix and stores the results in another matrix called `cosineMatrix`. The `printMatrix` method is used to display the original matrix and the cosine matrix.

When you run the `main` method, it will output the original matrix and the corresponding cosine matrix. You can modify the values in the `matrix` array to test the program with different input matrices.