Thedefinitionof is that and

since .

.

a) (proof by contradiction) Suppose A were invertible. Then, multiplying both sides by , which is a contradiction because 0 is not invertible.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?

Do exactly the same thing for b.