let A be the matrix

|4 1 0 0 0|

|0 4 1 0 0|

|0 0 4 1 0|

|0 0 0 4 1|

|0 0 0 0 4|

I am asked to find the algebraic multiplicity

and the geometric multiplicity

I think as it is an upper triangular matrix eigenvalues are the diagonal entries i.e. all 4,

4^5 so Am is 5, im not sure on the geometric multiplicity though. Any help appreciated!