1. The problem statement, all variables and given/known data Let A be a square matrix. a. Show that (I-A)^-1 = I + A + A^2 + A^3 if A^4 = 0. b. Show that (I-A)^-1 = I + A + A^2 + ... + A^n if A^(n+1) = 0. 2. Relevant equations n/a 3. The attempt at a solution I thought I'd want to use the fact that the multiplication of a matrix and its inverse is equal to I. So I started with (I-A)*(I + A + A^2 + A^3) = I. But that doesn't seem like the right direction...I'm not sure where to go from there.