Chapter 7, Problem 30P

Write a user-defined MATLAB function that calculates the determinant of a 3×3 matrix by using the formula:

$\det =A_{11}\left[\begin{array}{l}{A}_{22}{A}_{23}\\ A_{32}{A}_{33}\end{array}\right]-A_{12}\left[\begin{array}{l}{A}_{21}{A}_{23}\\ A_{31}{A}_{33}\end{array}\right]+A_{13}\left[\begin{array}{l}{A}_{21}{A}_{22}\\ A_{31}{A}_{32}\end{array}\right]$

For the function name and arguments, use d3 — det3by3 (A), where the input argument A is the matrix and the output argument d3 is the value of the determinant. Write the code of det3by3 such that it has a subfunction that calculates the 2×2 determinant. Use det3by3 for calculating the determinants of:

(a) $\left[\begin{array}{l}132\\ 654\\ 789\end{array}\right]$ (b) $\left[\begin{array}{l}-2.571\\ 5-3-2.6\\ 42-1\end{array}\right]$