I'm a bit bloqued on a little demontration.
A^4=0 , (I-A)^-1 = I²+A+A²+A³
Here is what i've done:
But it is prove in reverse...
The right way:
If you know that matrix A^4=0, how to prove that (I-A)^-1 = I²+A+A²+A³
But in ths case (harder I supose), I don't know how to do.
Can you help me?