Let A be a m x n matrix. Show that A^t A and AA^t are both symmetric.
If you guys could help me out and show what you did, it would be amazingly awesome. Thanks in advance.
If you guys could help me out and show what you did, it would be amazingly awesome. Thanks in advance.
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Recall that C is symmetric iff C^t = C.
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1) Note that
(A^t A)^t
= A^t (A^t)^t, since (AB)^t = B^t A^t
= A^t A, since (A^t)^t = A.
Hence, A^t A is symmetric.
2) Similarly, AA^t is symmetric (same argument as above).
I hope this helps!
----------------
1) Note that
(A^t A)^t
= A^t (A^t)^t, since (AB)^t = B^t A^t
= A^t A, since (A^t)^t = A.
Hence, A^t A is symmetric.
2) Similarly, AA^t is symmetric (same argument as above).
I hope this helps!