User 17SI.34SA - Mathematics Stack Exchange

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7

votes

4

answers

127

views

Finding solution in naturals to $a^b=b^a$ with the help of $f(x)=\frac{\ln(x)}{x}$

calculus

mar 9 at 19:22 amWhy 61.5k

1

7

votes

2

answers

245

views

Every partial order can be extended to a linear ordering

jan 5 at 17:25 Brian M. Scott 161k

5

votes

3

answers

129

views

Is $\varsigma$ equivalence relation?

elementary-set-theory relations

apr 1 at 0:39 Community♦ 1

1

4

votes

2

answers

63

views

If $p(2x+1)=p(x^2)$ for all $x\in\mathbb{R}$, then $p\equiv\text{const.}$

calculus polynomials

21h ago Aris 151

4

votes

1

answer

75

views

Chain of length $2^{\aleph_0}$in $ (P(\mathbb{N}),\subseteq)$

homework elementary-set-theory

dec 7 at 17:59 Asaf Karagila 95.9k

1

3

votes

3

answers

64

views

Determine if $\sum^{\infty}_{n=1}\int^{\frac{\sin n}{n}}_0\frac{\sin x}{x} \, dx $ is converges or diverges.

calculus real-analysis sequences-and-series integral

18h ago Norbert 21.2k

1

3

votes

1

answer

87

views

Stupid question about $1 - \frac{1}{2}-\frac{1}{4}+\frac{1}{3}- \frac{1}{6}-\frac{1}{8}+\frac{1}{5}\dots$

sequences-and-series

may 31 at 15:02 Hagen von Eitzen 47.3k

1

3

votes

3

answers

345

views

Infinite set as union of disjoint countable sets.

elementary-set-theory axiom-of-choice

dec 21 at 10:12 Asaf Karagila 95.9k

3

votes

3

answers

47

views

Nature of D-finite sets.

elementary-set-theory

dec 15 at 22:37 Saltekoff 1

2

votes

1

answer

31

views

Analysis of $\sum_{k=1}^{\infty}\frac{x^2}{(1+x^2)^k}$

calculus sequences-and-series

6h ago DonAntonio 50.7k

2

votes

4

answers

108

views

The sum $1+\frac{1}{3}+\frac{1}{5}+\frac{1}{7}+\cdots-(\frac{1}{2}+\frac{1}{4}+\frac{1}{6}+\cdots)$ does not exist.

sequences-and-series

may 31 at 17:31 marty cohen 7,519

2

votes

3

answers

106

views

Functional equation $f(xy)=f(x)+f(y)$

calculus functional-equations

may 4 at 1:20 Clement C. 1,551

2

votes

1

answer

70

views

Integral change of variable simple case proof

integration

apr 16 at 21:00 Halil Duru 1,006

2

votes

2

answers

62

views

Is $x_0$ local minimum/maximum or inflection point if $f'(x_0)=0$?

calculus

mar 9 at 16:23 Community♦ 1

1

2

votes

3

answers

171

views

Cardinality of all dense and countable sets of $\mathbb{R}$

general-topology elementary-set-theory

dec 6 at 9:21 Asaf Karagila 95.9k

2

votes

2

answers

103

views

Onto function and Power set cardinality.

homework elementary-set-theory

dec 6 at 7:30 Asaf Karagila 95.9k

2

votes

1

answer

36

views

Embedding $P(\mathbb{N})$ into $P_{\infty}(\mathbb{N})$

elementary-set-theory

nov 28 at 19:50 Asaf Karagila 95.9k

2

1

vote

2

answers

80

views

ExPreQ1: If $f>0$ is integrable on $[a,b]$, then $\sqrt{f}$ is integrable.

calculus integral

jun 12 at 22:07 Peter Tamaroff 28.7k

1

vote

1

answer

55

views

Proving $(\operatorname{ker}T)^{\perp}\subseteq \operatorname{Im} T^{*}$

linear-algebra

may 6 at 11:23 Scis 84

1

vote

0

answers

20

views

Darboux integrable periodic function is integrable on any closed and bounded interval

definite-integral

apr 27 at 2:53 17SI.34SA 421

1

vote

1

answer

51

views

Composition of step function with linear one.

functions

apr 15 at 15:44 Abel 5,177

1

vote

2

answers

110

views

Limit problem involving cube roots (without use of L'Hôpital's rule or Taylor series)

limit

jan 29 at 18:59 julien 25.6k

1

vote

1

answer

66

views

Well-ordering the set of all finite sequences.

elementary-set-theory

jan 5 at 0:36 Asaf Karagila 95.9k

1

vote

2

answers

73

views

Subset of $(P(\mathbb{N}),\subseteq)$

elementary-set-theory

dec 27 at 9:31 Asaf Karagila 95.9k

1

vote

1

answer

82

views

Unbounded family of functions from $\mathbb{N}$ to $\mathbb{N}$ [duplicate]

elementary-set-theory

nov 23 at 22:52 Andres Caicedo 25.3k

1

vote

1

answer

61

views

Union of equivalence relation

elementary-set-theory relations equivalence-relations

nov 5 at 11:47 coffeemath 7,016

1

vote

1

answer

62

views

Proving via axioms, that for given set, $A$, exist a set $\{(X,Y): X\subset Y \subset A \}$

elementary-set-theory

oct 26 at 17:35 Matt N. 15.6k

1

vote

2

answers

114

views

Question on Transitive Set.

elementary-set-theory

oct 26 at 12:23 Brian M. Scott 161k

0

votes

1

answer

35

views

Understanding $\sum^n_{i=1}\int_{(i-1)\pi}^{i\pi}|\frac{\sin x}{x}|\,dx\ge\sum^n_{i=1}\frac{1}{i\pi}\int_{(i-1)\pi}^{i\pi}|\sin x|\,dx$

calculus integration summation improper-integrals

jun 14 at 17:32 Stefan Hansen 9,443

0

votes

1

answer

13

views

Cauchy principal value and the “normal” definition.

improper-integrals

jun 9 at 10:30 Belgi 7,292

17SI.34SA

48 Questions