User Kasper - Mathematics Stack Exchange

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	2,313 reputation	bio	website		visits	member for	5 months
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9

22

votes

7

answers

1

kviews

Does mathematics require axioms?

apr 25 at 6:25 Matt E 57.9k

8

24

votes

2

answers

830

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Proof by contradiction vs Prove the contrapositive

logic proof-strategy proof-theory

jan 31 at 1:27 amWhy 54.6k

1

vote

4

answers

542

views

Find the rotation axis and angle of a matrix

linear-algebra

dec 18 at 19:52 Cameron Buie 27.6k

4

8

votes

8

answers

502

views

How do I prove that a function is well defined?

functions logic proof-writing

feb 26 at 0:02 Asaf Karagila 90.8k

1

5

votes

10

answers

493

views

How to define the $0^0$? [duplicate]

real-analysis

dec 17 at 15:30 MJD 20.8k

10

23

votes

1

answer

492

views

About Euclid's Elements and modern video games

geometry euclidean-geometry education math-software

may 1 at 21:30 Kasper 2,313

2

votes

6

answers

382

views

Writing mathematical presentations using mathjax [closed]

math-software

mar 21 at 23:05 Robert Smith 989

7

votes

3

answers

324

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Does the $\sum_{n=1}^\infty \frac{1}{n\sqrt[n]{n}}$ converge?

homework real-analysis sequences-and-series

feb 11 at 17:23 André Nicolas 161k

3

votes

3

answers

210

views

$\int_a^b f(t)g(t)dt=f(x)\int_a^b g(t)dt$

real-analysis integral

apr 9 at 20:10 robjohn♦ 59.5k

0

votes

3

answers

203

views

WLOG means losing generality?

terminology

dec 13 at 19:33 Thomas Andrews 29.8k

4

votes

2

answers

177

views

Does the series $\sum \frac{x^n}{1+x^n}$ converge uniformly on $x\in [0,1)$?

homework real-analysis

mar 5 at 14:44 rschwieb 20.8k

1

vote

4

answers

157

views

How can I interpret $\max(X,Y)$?

probability-theory probability-distributions

jan 14 at 19:22 Michael Hardy 48k

2

votes

4

answers

157

views

Are the groups $\mathbb{C}$ and $\mathbb{R}$ isomorphic?

abstract-algebra group-theory

mar 21 at 19:52 Babak S. 27.6k

3

2

votes

0

answers

152

views

Is the $ϵ,δ$ definition of a limit not well-defined?

real-analysis analysis soft-question proof-theory

apr 18 at 12:56 Kasper 2,313

5

votes

3

answers

151

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$\sum a_n$ converges $\iff \sum (\sqrt{1+a_n}-1)$ converges

homework real-analysis sequences-and-series

feb 13 at 21:28 Mhenni Benghorbal 14k

1

12

votes

4

answers

149

views

What is symmetric about the symmetric group? [duplicate]

abstract-algebra group-theory symmetric-groups

feb 28 at 14:00 Tobias Kildetoft 4,726

3

2

votes

3

answers

144

views

How do I prove that $\lim_{x→0} x⋅\ln x=0$

real-analysis integral

dec 13 at 22:40 N. S. 27.6k

1

vote

2

answers

142

views

Arithmetic mean is at least as large as the geometric mean: $\frac{(s_1+…+s_n)}{n}\geq(s_1 \cdot …\cdot s_n)^{1/n}$

homework real-analysis

feb 7 at 19:13 karakfa 618

1

6

votes

1

answer

140

views

Does $\sum_{n=3}^\infty \frac {1}{(\log n)^{\log(\log(n)}}$ converge?

real-analysis sequences-and-series

mar 5 at 20:24 Arjang 2,437

1

vote

3

answers

138

views

Prove that a simple graph with $2n$ vertices without triangles has at most $n^2$ lines.

graph-theory

feb 19 at 16:26 Louis 555

4

votes

1

answer

134

views

$f$ continous at $x_0$ $⇒\lim_{h→0}∫_{x_0}^{x_0+h}\frac{f(t)}{h}=f(x_0)$

real-analysis limit integration continuity

jan 17 at 19:32 Community♦ 1

4

votes

5

answers

133

views

Let $x,y$ in a group G with uneven order. Let $x^2=y^2$. Show that $x=y$.

abstract-algebra group-theory

mar 24 at 21:52 Community♦ 1

1

4

votes

4

answers

130

views

Prove that every isometry on $\mathbb{R}^2$ is bijective

real-analysis geometry

feb 18 at 17:34 André Nicolas 161k

2

votes

3

answers

123

views

How to calculate $\overline{\cos \phi}$

complex-numbers

dec 18 at 16:38 lab bhattacharjee 28.6k

3

votes

0

answers

115

views

Direct proof that $\sqrt{2}$ is irrational? [duplicate]

irrational-numbers alternative-proof

dec 30 at 1:03 Mario Carneiro 2,845

1

vote

2

answers

114

views

Determine the exact interval of convergence of $\sum x^{n!}$

homework real-analysis sequences-and-series

feb 15 at 16:57 tetori 2,821

1

6

votes

2

answers

114

views

Is this correct? $rH=Hr^{-1}$

abstract-algebra group-theory

mar 14 at 22:36 Andreas Caranti 15.1k

2

votes

2

answers

113

views

What is the negation of a converging series?

sequences-and-series

dec 29 at 21:42 Christian Blatter 32.6k

2

3

votes

2

answers

111

views

A sequel for Elementary Analysis by Ross?

real-analysis analysis reference-request multivariable-calculus

apr 5 at 12:28 Kasper 2,313

3

votes

2

answers

104

views

$H ≤G$ means $H$ is a subgroup of $G$?

abstract-algebra group-theory notation

apr 4 at 1:56 amWhy 54.6k

Kasper

114 Questions