Cayley-Hamilton Theorem

For a square matrix , identity matrix , and zero matrix , the following holds:
This is called the Cayley-Hamilton Theorem.

[Proof] Given ,



Thus,


[Note] For , the Cayley-Hamilton theorem gives . However, matrix is not unique in satisfying the equation . For example, also satisfies .


Example. Given the matrix satisfies the following equation.
Find the value of for the constants and .

 Solution
Since ( is a real number), by the Cayley-Hamilton theorem,

Therefore,