User Sine of the Time

7 votes

3 answers

390 views

Evaluating $\int_0^{\pi/2} \frac{\sqrt{\tan x}}{\sin x(\cos x+\sin x)}\mathrm{d}x$

asked Aug 1, 2023 at 10:04

5 votes

1 answer

123 views

Finding an explicit formula for the projection on a subspace of an Hilbert space

asked Dec 17, 2023 at 20:08

3 votes

1 answer

148 views

Showing that $\mathbb{R}^2/\sim$ is Hausdorff where $x\sim y \iff$ $(x=y\,\, \text{or}\,\, x,y \in $ $\{(x,y)\in \mathbb{R}^2\,\,|\,\, |y|\leq e^x\}$)

asked Dec 31, 2022 at 23:11

3 votes

1 answer

131 views

Fundamental group of a difference of topological spaces

asked Jan 7, 2023 at 16:15

3 votes

1 answer

83 views

For which $p\in [1,+\infty]$ is the following operator continuous?

asked Jan 23 at 22:42

1 vote

1 answer

74 views

Fundamental group and doubt about covering map

asked Dec 30, 2022 at 16:40

1 vote

1 answer

63 views

Example of a function such that $f\in C(\Bbb R)$, $f\in L^2\setminus L^1$ and $f(n)=n$ for all $n\ge 1$, $n\in \Bbb N$

asked Dec 18, 2023 at 1:11

1 vote

1 answer

64 views

Finding an explicit formula for the projection on a subspace of $\ell^2$

asked Dec 24, 2023 at 21:25

0 votes

1 answer

108 views

Proving that a function between two specific topological spaces can't be both continuous and injective

asked Dec 29, 2022 at 22:04

-1 votes

1 answer

137 views

Findind the biggest $k$ such that $e^x\ge1+kx^2$

asked Nov 14, 2022 at 8:13

-1 votes

1 answer

126 views

Covering maps $p:\mathbb{R}^n\to \mathbb{R}^2$

asked Jan 7, 2023 at 8:38

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11 Questions

Evaluating $\int_0^{\pi/2} \frac{\sqrt{\tan x}}{\sin x(\cos x+\sin x)}\mathrm{d}x$

Finding an explicit formula for the projection on a subspace of an Hilbert space

Showing that $\mathbb{R}^2/\sim$ is Hausdorff where $x\sim y \iff$ $(x=y\,\, \text{or}\,\, x,y \in $ $\{(x,y)\in \mathbb{R}^2\,\,|\,\, |y|\leq e^x\}$)

Fundamental group of a difference of topological spaces

For which $p\in [1,+\infty]$ is the following operator continuous?

Fundamental group and doubt about covering map

Example of a function such that $f\in C(\Bbb R)$, $f\in L^2\setminus L^1$ and $f(n)=n$ for all $n\ge 1$, $n\in \Bbb N$

Finding an explicit formula for the projection on a subspace of $\ell^2$

Proving that a function between two specific topological spaces can't be both continuous and injective

Findind the biggest $k$ such that $e^x\ge1+kx^2$

Covering maps $p:\mathbb{R}^n\to \mathbb{R}^2$