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P6 Topic 2: Matrix algebra
2 x 2 and 3 x 3 determinants backmore
The determinant of the matrix A
2x2 matrix
is det(A) = ad - bc.

Enter values into the matrices A or B. You can then find out the determinant. Can you find any values that make either determinant zero?

Matrix A :

Matrix B :
Determinant

Summary
Clearly the 2x2 matrix is zero when ad=bc. There are many ways of making the 3x3 matrix zero. For example if any two rows or columns are identical, or if any row or column is a multiple of any other row or column.
JavaScript interactive pages based on the Java Script Linear Algebra Calculator by Marcus Kazmierczak