1.Let B an nxn matrix such that B^4=0
Show that A=I-B is invertible and A^-1 = I+B+B^2+B^3?
2 Let A an nxn Matrix
a.If A^2=0 show that A is not Invertible
b. If A^2= A and A is not the identity, show that A is not Invertible.
plz help.. i couldnt seem to figure it out?