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age 25
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seen 21 hours ago

If you solve this I'd award you with 500rep


2d
revised Finding characteristic equation of problem and solve recurrence relation
deleted 12 characters in body
Aug
16
comment Show that $\mathbb Z[x]$ and $\mathbb Q_{>0}$ are isomorphic
This question has been already asked
Aug
12
revised If $AB = I$ then $BA = I$
Tuning this into a correct argument.
Aug
8
revised How prove that $\max(|f(1)|,|f(2)|,|f(3)|,|f(4)|)\geq \frac{1}{2}$ if $f(x) = \cos(Ax)+\cos(Bx)$?
edited title
Aug
6
revised Proof for '$AB = I$ then $BA = I$' without Motivation?
Formatting.
Aug
6
reviewed Close Simplifying this sigma notation
Aug
6
revised Show that a finite group with certain automorphism is abelian
english
Aug
6
comment How to prove that $\det\left[\pmatrix{u_1 & v_1\\ u_2 & v_2\\ u_3 & v_3}\pmatrix{s_1 & s_2 & s_3\\ t_1 & t_2 & t_3}\right]=0$?
@Nishant you're right, let me correct myself: Let $A$ be a $m\times n$ matrix and $B$ be a $n\times m$ matrix. If $n\lt m$ then $AB$ is not invertible.
Aug
5
revised Trouble understanding solution to abstract algebra problem
Typo, formatting.
Aug
5
revised Prove that the polynomial $q$ exists.
Formatting.
Aug
3
comment Proof for '$AB = I$ then $BA = I$' without Motivation?
I've found this which solves it for $n=2$.
Jul
31
answered Let $T:V\to W$ be a linear transformation. If $\dim V> \dim W$ then $T$ is not injective. True or false?
Jul
31
revised Let $T:V\to W$ be a linear transformation. If $\dim V> \dim W$ then $T$ is not injective. True or false?
edited title
Jul
24
revised Evaluate the limit: $\lim_{x\to \infty}$
formatting
Jul
22
revised Is the Axiom of Choice necessary to prove $\mathbb R \approx \mathcal P(\omega)$?
added 9 characters in body
Jul
21
revised If $AB = I$ then $BA = I$
added 2 characters in body
Jul
14
revised How does one prove that if $f$ and $g$ are linear functionals on $V$ such that $h=fg$ is also a linear functional, then either $f=0$ or $g=0?$
Formatting
Jul
12
revised Existence of rational sequence such that a polynomial is split over $\Bbb{Q}$
Avoiding trivial solutions
Jul
12
comment Existence of rational sequence such that a polynomial is split over $\Bbb{Q}$
Yes, here the roots are not necessarily distinct. There should be some literature about this. Both seems like very natural questions, I wonder where we can find some.
Jul
10
answered The annihilator of an intersection