User TheWanderer

9 votes

How does one evaluate $1+2-3-4+5+6-7-8+\cdots+50$?

answered Oct 28, 2017 at 10:00

5 votes

How many connected components does $\mathrm{GL}_n(\mathbb R)$ have?

answered Oct 16, 2014 at 15:30

5 votes

Accepted

Proof that if $a$ divides $b$ and $a$ does not divide $c$ then $a$ does not divide $c - b$

answered Sep 23, 2017 at 16:06

4 votes

Closed unit disk is not homeomorphic to the real plane R^2?

answered Aug 28, 2017 at 11:51

3 votes

Why is: $\frac{x^2}{(x^2-1)(x^2+1)} = \frac{1}{2}\left(\frac{1}{x^2-1}\right)+\frac{1}{2}\left(\frac{1}{x^2+1}\right)$

answered Jun 12, 2017 at 14:57

3 votes

Is it necessary to write about the set?

answered Mar 8, 2018 at 20:51

3 votes

Accepted

Fundamental group of real $3\times 3$ matrices with rank $1$

answered Dec 31, 2014 at 16:03

3 votes

The functional equation $\frac{f(x)}{f(1-x)} = \frac{1-x}{x}$

answered Mar 31, 2017 at 12:41

2 votes

If $f$ is bijective then $f(A^c) = f(A)^c$?

answered Mar 31, 2017 at 12:48

2 votes

Accepted

Complex Analysis-Proof Verification

answered Mar 8, 2018 at 20:59

2 votes

Accepted

Notation for "the equation of the line $ \overleftrightarrow{AB} $ is $ y=mx+c $"

answered Mar 9, 2018 at 9:05

2 votes

Tips/Tricks for beginners in Analysis and Recommendation

answered Mar 9, 2018 at 9:02

1 vote

Derivative product rule $\frac{d}{dx}\sqrt{xe^{-3x}}$

answered Mar 10, 2018 at 9:29

1 vote

What's dim(Null(A)) + dim(Col(A))

answered Apr 15, 2018 at 13:20

1 vote

Accepted

Simplify $3^{2018}\pmod{31}$

answered Mar 8, 2018 at 21:16

1 vote

Example of hypergraph

answered Feb 26, 2018 at 20:36

1 vote

Linear independence of a set of solutions and the Wronskian

answered Jan 16, 2017 at 10:16

1 vote

Accepted

Solve the congruence $9x \equiv −3 \pmod{24}$. Give your answer as a congruence to the smallest possible modulus, and as a congruence modulo 24.

answered Mar 31, 2017 at 13:02

1 vote

Is a linear equation always a straight line?

answered Mar 31, 2017 at 19:07

1 vote

Proving an interesting property of absolute values: $\frac{|x+y|}{1+|x+y|}\le\frac{|x|}{1+|y|}+\frac{|y|}{1+|y|}$

answered May 12, 2017 at 9:24

1 vote

How to define/call this process?

answered Jun 1, 2017 at 9:36

0 votes

Abstract Algebra: understanding the subject inside out

answered Mar 31, 2017 at 12:54

0 votes

Explain this passage on the proof that the curvature of the vector function $r(t)$ is $\frac{|r'(t) \times r''(t)|}{ |r'(t)|³}$?

answered Jan 20, 2015 at 12:24

0 votes

Show that $a_{n+1} =a_n + \frac{1}{3^n}$ defines a Cauchy sequence

answered Sep 12, 2017 at 16:05

0 votes

Proving an inequality when a graph is not connected

answered Mar 7, 2018 at 10:09

0 votes

Computing generators of polynomial rings (software/algorithm)

answered Jul 5, 2022 at 13:43

0 votes

Accepted

Find if two variables function is differentiable: $f(x,y)=\frac{x(1-\cos x)}{\sin(x^2+y^2)}$

answered Jun 23, 2018 at 8:20

0 votes

Accepted

Divergence of the sequence $s_n = n$, i.e., the sequence $1,2,3, \dots n$

answered Mar 11, 2018 at 9:48

0 votes

Order of each element in the given group

answered Mar 9, 2018 at 21:33

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29 Answers

How does one evaluate $1+2-3-4+5+6-7-8+\cdots+50$?

How many connected components does $\mathrm{GL}_n(\mathbb R)$ have?

Proof that if $a$ divides $b$ and $a$ does not divide $c$ then $a$ does not divide $c - b$

Closed unit disk is not homeomorphic to the real plane R^2?

Why is: $\frac{x^2}{(x^2-1)(x^2+1)} = \frac{1}{2}\left(\frac{1}{x^2-1}\right)+\frac{1}{2}\left(\frac{1}{x^2+1}\right)$

Is it necessary to write about the set?

Fundamental group of real $3\times 3$ matrices with rank $1$

The functional equation $\frac{f(x)}{f(1-x)} = \frac{1-x}{x}$

If $f$ is bijective then $f(A^c) = f(A)^c$?

Complex Analysis-Proof Verification

Notation for "the equation of the line $ \overleftrightarrow{AB} $ is $ y=mx+c $"

Tips/Tricks for beginners in Analysis and Recommendation

Derivative product rule $\frac{d}{dx}\sqrt{xe^{-3x}}$

What's dim(Null(A)) + dim(Col(A))

Simplify $3^{2018}\pmod{31}$

Example of hypergraph

Linear independence of a set of solutions and the Wronskian

Solve the congruence $9x \equiv −3 \pmod{24}$. Give your answer as a congruence to the smallest possible modulus, and as a congruence modulo 24.

Is a linear equation always a straight line?

Proving an interesting property of absolute values: $\frac{|x+y|}{1+|x+y|}\le\frac{|x|}{1+|y|}+\frac{|y|}{1+|y|}$

How to define/call this process?

Abstract Algebra: understanding the subject inside out

Explain this passage on the proof that the curvature of the vector function $r(t)$ is $\frac{|r'(t) \times r''(t)|}{ |r'(t)|³}$?

Show that $a_{n+1} =a_n + \frac{1}{3^n}$ defines a Cauchy sequence

Proving an inequality when a graph is not connected

Computing generators of polynomial rings (software/algorithm)

Find if two variables function is differentiable: $f(x,y)=\frac{x(1-\cos x)}{\sin(x^2+y^2)}$

Divergence of the sequence $s_n = n$, i.e., the sequence $1,2,3, \dots n$

Order of each element in the given group