Răspuns:
Explicație pas cu pas:
[tex]A=\left(\begin{array}{ccc}2&1\\4&2\\\end{array}\right)[/tex]
[tex]f(A)=A^{2} -4A[/tex]
[tex]A^{2} =A\cdot A=\left(\begin{array}{ccc}2&1\\4&2\\\end{array}\right)\cdot \left(\begin{array}{ccc}2&1\\4&2\\\end{array}\right)=\left(\begin{array}{ccc}8&4\\16&8\\\end{array}\right)[/tex]
[tex]f(A)=\left(\begin{array}{ccc}8&4\\16&8\\\end{array}\right)-\left(\begin{array}{ccc}8&4\\16&8\\\end{array}\right)=\left(\begin{array}{ccc}0&0\\0&0\\\end{array}\right)=O_{2}[/tex]
