Question

Find A², where A = $\left[\begin{array}{ccc}4&2\\-1&1\end{array}\right]$

Answer 1

Answer:

$A^{2}=\left[\begin{array}{ccc}14&10\\-5&-1\end{array}\right]$

Step-by-step explanation:

If  

$A=\left[\begin{array}{ccc}4&2\\-1&1\end{array}\right]$  and    

So, to find  A²

$A^{2}=A\times A=\left[\begin{array}{ccc}4&2\\-1&1\end{array}\right]\times \left[\begin{array}{ccc}4&2\\-1&1\end{array}\right]$

  $A^{2}=\left[\begin{array}{ccc}4(4)+2(-1)&4(2)+2(1)\\-1(4)-1(1)&-1(2)+1(1)\end{array}\right]$

So

$A^{2}=\left[\begin{array}{ccc}14&10\\-5&-1\end{array}\right]$