interpretation of $A^T A$
3150
Is there an intuitive interpretation of $A^TA$ for a data matrix $A$?
152665
$A^TA+I$ is always invertible?
55377
Non-zero eigenvalues of $AA^T$ and $A^TA$
66610
Finding a correspondence between $\{0,1\}^A$ and $\mathcal P(A)$
110086
Let $A$ be an $m \times n$ matrix. Show $A^TA$ and $AA^T$ have the same eigenvalues
12272
Why $a$ is not an essential singularity and how $f$ can be extended
60598
Matrix $A^T A$ as sum of outer products
130253
Differentiating $\mbox{tr} (ABA^TC)$ w.r.t. $A$
117533
$|A-\lambda I|$ and $|\lambda I-A|$
55018
Prove that $A^*A + I$ is invertible
83798
Does $A$ a UFD imply that  $A[T]$ is also a UFD?
128764
How does $y[x] = a x^r$ when $y'[x] = \frac{(r y[x])}{x}$ and $y[1] = a$
101861
How do you prove that $tr(B^{T} A )$ is a inner product?
28565
Prove $\operatorname{rank}A^TA=\operatorname{rank}A$ for any $A\in M_{m \times n}$
112707
Must $Q^\mathsf{T}Q = I$ if $(Qx)^\mathsf{T}(Qx) = x^\mathsf{T}x$
79276
Find $\min(\operatorname{trace}(AA^T))$ for invertible $A_{n\times n}$
93825
Fourier transform of power function $t^\alpha$