Chrystomath's user avatar
Chrystomath's user avatar
Chrystomath's user avatar
Chrystomath
  • Member for 10 years, 9 months
  • Last seen this week
17 votes

Why are subsets of compact sets not compact?

11 votes
Accepted

For $n \times n$ matrices $A$ and $B$, if $(A^i - B^i)x = 0$ for $i = 1, \dots,\ n$, does $(A^{n+1} - B^{n+1}) x = 0$?

9 votes
Accepted

find maximum value of $\frac x{(x^2+1)^{\frac32}}$ with AM-GM inequality

9 votes
Accepted

Does ONLY the ellipse have these properties?

9 votes

Bounds of $1^n + 2^{n-1} + 3^{n-2} + \cdots + n^1$

9 votes
Accepted

What are left and right singular vectors in SVD?

7 votes
Accepted

Determine the minimum of $\frac{\int_0^1{x^2\left( f'\left( x \right) \right) ^2 dx}}{\int_0^1{x^2\left( f\left( x \right) \right) ^2dx}}$

7 votes

Topological vector space with discrete topology is the zero space

7 votes
Accepted

Product of n integers of AP is divisible by $n!$

6 votes

Convergence of composition of functions sequences

6 votes
Accepted

What vector x will maximize the norm of $\|Ax\|_2 / \|x\|_2$ (norm 2)

6 votes
Accepted

Hilbert space with two equivalent norms

6 votes
Accepted

Prove $\log|e^z-z|\leq |z|+1$

6 votes
Accepted

If $(X,| \cdot|)$ is isometrically isomorphic with $(X,\|\cdot \|)$ is it always true that the norms are equivalent??

6 votes
Accepted

Inequality proof $ay + bz + cx < 1$ with conditions

5 votes
Accepted

Is there a natural number $n$ such that $\underbrace{20182018 \cdots 20182018}_{n \text{ times}}$ is multiple of $2019.$

5 votes
Accepted

To prove that an operation is well-defined in modular arithmetic

5 votes

Find all functions which satisfy $f(m^2+n^2)=f(m)^2+f(n)^2$ $\forall\space m,n\in\Bbb{N}$ and $f(1)>0$

5 votes
Accepted

Evaluate the limit $\lim\sqrt[n]{\frac{1}{n!}\sum(m^m)}$

5 votes
Accepted

After applying a sequence of involutory real matrices to a vector, is the norm of this vector bounded from below?

5 votes
Accepted

Why is Isom(E,F) open in the set of bounded linear operators between E and F?

5 votes
Accepted

A proof that $\langle u,v\mid u^4=v^3=1, uv=v^2u^2\rangle$ defines the trivial group.

5 votes

Integer solutions to $\sqrt{ax^2+1}$ and the unusually large solutions

4 votes

Prove or disprove : $\sqrt{1 + \sqrt{4+\sqrt{16+\sqrt{256...}}}} = \sqrt{2+\sqrt{5}}$

4 votes

Is there a solution to the functional equation $f(x)=2\log(x)^2f\left(x^\frac{3}{8}\right)^2f\left(x^\frac{1}{4}\right)^2$?

4 votes
Accepted

Does positive row scaling matrix don't change a sign of matrix's eigenvalue?

4 votes

Number of attempts to see all faces $1, 2, 3, ..., 6$ when rolling a dice?

4 votes

Intersection of path-connected sets in $\mathbb{R}^{n}$

4 votes

Find the formula to get $0$ or $1$ when input is greater than a threshold

4 votes
Accepted

How to prove that if f is continuous that the exponential function satisfies the functional equation?

1
2 3 4 5
15