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comment Does every invertible matrix A has a matrix B such that A=Adj(B)?
Hint: $\operatorname{adj}(\operatorname{adj}(A)) = (\det A)^{n-2} A$
Apr
29
answered Result about Matrices of form $B(AB)^{-1}A$
Apr
29
comment Result about Matrices of form $B(AB)^{-1}A$
So, have you run your script? What's the result?
Apr
29
comment Closest positive definite matrix to arbitrary one
The set of all positive definite matrices is not closed. So, in general, unless your matrix is PD right from the start, no solution exists. Maybe you are looking for the closest positive semidefinite matrix?
Apr
27
answered Pseudoinverse (Moore-Penrose) of rank 1 matrix is a scalar multiple of its transpose
Apr
26
comment An inverse spectrum problem in linear algebra,
No, the realising matrix is not necessarily symmetric. Every 2x2 asymmetric nonnegative matrix will realise some real spectrum. E.g. $\pmatrix{1&1\\ 0&1}$ has spectrum $\{1,1\}$. It just happens that when $n=2$, every spectrum of a nonnegative matrix is realisable by some symmetric nonnegative matrix.
Apr
26
reviewed Close Question regarding Sum Notation in the least squares formula
Apr
26
reviewed Close What means to expand determinant from first column?
Apr
26
reviewed Close Let $f(x)= \begin{cases} 1, & \text{if $x \in \Bbb Q \cap [a,b]$} \\ -1, & \text{if $x \in \Bbb I \cap[a,b]$} \end{cases}$
Apr
26
reviewed Close Prove that $f$ is a constant function.
Apr
26
reviewed Close Expected value of $X^{2n}$ where $X \sim N(0,1)$
Apr
26
reviewed Close $g: (U \times U - D) \to \mathbb{R}$ is continuous, $D$ diagonal?
Apr
26
reviewed Close If there are $74$ heads and $196$ legs, how many horses and humans are there?
Apr
26
reviewed Leave Open Why four roots to this equation: $(7x+1)^{1 \over 3}+(8+x-x^2)^{1 \over 3}+(x^2-8x-1)^{1 \over 3}=2$
Apr
26
reviewed Close Combination of the arrangement of sets
Apr
26
revised If $\frac{4z+17}{18} - \frac{13z-2}{17z-32} + \frac{z}{3} = \frac{z+60}{36}$ , find the value of $z$.
edited tags
Apr
25
comment If matrix $A$ is similar to matrix $D$ and $B$ is similar to $E$, than: $AB$ is similar to $DE$?
And the answer to the question in the title is also "no". Consider the case where $A=B=D$ is the 2x2 nilpotent Jordan block and $E=A^T$.
Apr
25
revised Point closest to a set four of lines in 3D
added 417 characters in body
Apr
23
revised Special skew-symmetric matrices
added 159 characters in body
Apr
22
answered Special skew-symmetric matrices