User HyperGroups

14 votes

2 answers

9k views

Prove: the set of zeros of a continuous function is closed.

asked Jul 21, 2013 at 14:54

10 votes

1 answer

6k views

questions about Rudin's summation by parts

asked Jul 1, 2013 at 16:46

8 votes

12 answers

27k views

limit question: $\lim\limits_{n\to \infty } \frac{n}{2^n}=0$

asked Jun 30, 2013 at 15:13

8 votes

4 answers

1k views

Why the members of $\mathbb R$ will be certain subsets of $\mathbb Q$?

asked Jun 23, 2013 at 11:04

7 votes

5 answers

2k views

Prove:$|x-1|+|x-2|+|x-3|+\cdots+|x-n|\geq n-1$

asked Jul 9, 2013 at 15:03

5 votes

3 answers

96 views

What conditions hold $f\left(f^{-1}(x)\right)=x$

asked Jul 15, 2013 at 6:23

4 votes

7 answers

772 views

prove：$\left|x+\frac{1}{x}\right|\geq 2$ [duplicate]

asked Jul 9, 2013 at 13:11

4 votes

1 answer

241 views

$\lim \limits_{h\to 0} \frac{e^h-1}{h}=1$ and the relation with $\sin'(x)=\cos(x)$

asked Jul 21, 2013 at 13:35

3 votes

0 answers

89 views

How to understand Abel's sentence

asked Nov 29, 2016 at 8:47

3 votes

1 answer

202 views

There is a real number $\alpha >1$ such that $\Bigl\lfloor2^{2^{{.}^{{.}^{{.}^{2^{\alpha }}}}}}\Bigr\rfloor$ is prime for all $n\geq 1$

asked Jul 10, 2013 at 2:28

3 votes

3 answers

213 views

$(\lambda X+\mu Y)(a)=\lambda X(a)+\mu Y(a)$

asked Jul 22, 2013 at 5:58

3 votes

2 answers

78 views

Prove: For all $n\geq 1$, $a_{n+1}-a_n<8^ka_n^{\left(1-\frac{1}{k}\right)^3}$.

asked Jul 23, 2013 at 2:09

3 votes

2 answers

201 views

Are Mod of Rings are the same to Quotient Groups?

asked Jun 29, 2013 at 3:11

3 votes

4 answers

2k views

relation between arithmetic series and `square` arithmetic series

asked Jun 29, 2013 at 3:49

2 votes

2 answers

277 views

$\sum _{p\leq n}\frac{1}{p}=C+\ln \ln n+O\left(\frac{1}{\ln n}\right)$

asked Jun 29, 2013 at 10:40

2 votes

1 answer

305 views

prove equation has no rational root.

asked Jun 11, 2013 at 16:51

2 votes

1 answer

158 views

Proof $d(x)=\text{GCD}(f(x),g(x))$

asked Jun 22, 2013 at 6:38

2 votes

3 answers

103 views

A proposed proof by induction of $1+2+\ldots+n=\frac{n(n+1)}{2}$

asked Jun 26, 2013 at 12:12

2 votes

0 answers

91 views

A proposed solution of projectile's height and range

asked Jun 27, 2013 at 3:22

2 votes

2 answers

136 views

Can one show me how to plot this graph by hand (composition).

asked Jun 27, 2013 at 4:23

2 votes

1 answer

95 views

Solve for the domain of x

asked Jun 28, 2013 at 0:57

2 votes

0 answers

137 views

Proof reading of one college-Algebra-polynomial-thereom.

asked May 28, 2013 at 8:53

2 votes

0 answers

93 views

proof about an polynomial proposition.

asked May 31, 2013 at 15:10

2 votes

2 answers

71 views

The difference with sup and without sup

asked Jul 3, 2013 at 4:04

2 votes

2 answers

326 views

The union of a countable set of countable sets?

asked Jul 8, 2013 at 4:08

2 votes

1 answer

133 views

How close could two local maxima be?

asked Jul 15, 2013 at 1:42

2 votes

1 answer

115 views

Where can I get all mathematician's birth day and death day?

asked Sep 7, 2013 at 11:49

2 votes

1 answer

742 views

un-named theorems in Baby Rudin

asked Sep 13, 2013 at 11:39

2 votes

4 answers

5k views

Bounded above implies there exists a $\sup B$?

asked Jul 25, 2013 at 14:39

1 vote

0 answers

83 views

The difference of change of bases and change of basis

asked Aug 4, 2013 at 7:20

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55 Questions

Prove: the set of zeros of a continuous function is closed.

questions about Rudin's summation by parts

limit question: $\lim\limits_{n\to \infty } \frac{n}{2^n}=0$

Why the members of $\mathbb R$ will be certain subsets of $\mathbb Q$?

Prove:$|x-1|+|x-2|+|x-3|+\cdots+|x-n|\geq n-1$

What conditions hold $f\left(f^{-1}(x)\right)=x$

prove：$\left|x+\frac{1}{x}\right|\geq 2$ [duplicate]

$\lim \limits_{h\to 0} \frac{e^h-1}{h}=1$ and the relation with $\sin'(x)=\cos(x)$

How to understand Abel's sentence

There is a real number $\alpha >1$ such that $\Bigl\lfloor2^{2^{{.}^{{.}^{{.}^{2^{\alpha }}}}}}\Bigr\rfloor$ is prime for all $n\geq 1$

$(\lambda X+\mu Y)(a)=\lambda X(a)+\mu Y(a)$

Prove: For all $n\geq 1$, $a_{n+1}-a_n<8^ka_n^{\left(1-\frac{1}{k}\right)^3}$.

Are Mod of Rings are the same to Quotient Groups?

relation between arithmetic series and `square` arithmetic series

$\sum _{p\leq n}\frac{1}{p}=C+\ln \ln n+O\left(\frac{1}{\ln n}\right)$

prove equation has no rational root.

Proof $d(x)=\text{GCD}(f(x),g(x))$

A proposed proof by induction of $1+2+\ldots+n=\frac{n(n+1)}{2}$

A proposed solution of projectile's height and range

Can one show me how to plot this graph by hand (composition).

Solve for the domain of x

Proof reading of one college-Algebra-polynomial-thereom.

proof about an polynomial proposition.

The difference with sup and without sup

The union of a countable set of countable sets?

How close could two local maxima be?

Where can I get all mathematician's birth day and death day?

un-named theorems in Baby Rudin

Bounded above implies there exists a $\sup B$?

The difference of change of bases and change of basis