- #1
Roni1985
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Homework Statement
Let A be an idempotent matrix (A^2=A)
a) show that I-A is also idempotent
b) show that I+A is nonsingular and (I+A)^(-1)=I-(1/2)*A
Homework Equations
The Attempt at a Solution
I managed to solve part a, but have a little problem solving b.
I tried
(I+A)*(I+A)^(-1)=(?)I
but didn't know how to treat (I+A)^(-1)
Thanks,
Roni.