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Linear Algebra

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Moderate

Matrix FOIL

LINALG-NXJGHM

If $A$ and $B$ are square matrices of the same size, which of the following conditions will guarantee that:

$$(A+B)(A+B)=A^2+2AB+B^2$$

A

$A$ is invertible

B

$tr(A)=0$

C

$A=cI$, i.e. a scalar multiple of the identity matrix

D

All of the above