To understand Caley-Hamilton theorem you have to know about characteristic polynomial.
If A is a square matrix of of size n * n, and I is identity matrix of the same size as A. Then determinant |A-λI| will result in an equation of the form.
The theorem states that characteristic equation of a square matrix is satisfies by itself.
I will explain it using a 2 × 2 matrix
Theorem is very important result from linear algebra. Which is a lot of applications in matrix and polynomial related problem. In this post, I have explained the theorem in a very concise form. Hope it will help you for further study of linear algebra and, further, you will also apply somewhere.