Precalculus (6th Edition) Blitzer

The inverse is $A=\left[ \begin{matrix} 0.6 & 0 & -0.4 & 0.2 \\ 0.2 & 0 & 0.2 & -0.1 \\ 0 & 1 & 0 & 0 \\ -1.2 & 0 & 0.8 & 0.1 \\ \end{matrix} \right]$.
Consider the given matrix, $A=\left[ \begin{matrix} 1 & 2 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 1 & 3 & 0 & 1 \\ 4 & 0 & 0 & 2 \\ \end{matrix} \right]$ We have to find the inverse of matrix $A$ by using a calculator. We will follow the steps given below: (1) We select the matrix $A$ from the matrix edit menu and then enter or accept the dimensions. (2) Use ${{2}^{nd}}$ and press the matrix button. (3) Select the matrix $A$ and use the function ${{X}^{-1}}$ for the inverse of matrix $A$ and press enter. (4) We find the ${{A}^{-1}}$ Therefore, the inverse of the matrix $A$ is, $\left[ \begin{matrix} .6 & 0 & -.4 & .2 \\ .2 & 0 & .2 & -.1 \\ 0 & 1 & 0 & 0 \\ -1.2 & 0 & .8 & .1 \\ \end{matrix} \right]$ Now, check the result to show that $A{{A}^{-1}}=I$. We multiply matrix $A$ with ${{A}^{-1}}$ to obtain the identity matrix. Hence, the inverse of the given matrix is correct.