User Oria Gruber

20 votes

7 answers

3k views

There is no smallest infinity in calculus?

asked Sep 17, 2014 at 18:07

19 votes

3 answers

17k views

Generating multivariate normal samples - why Cholesky?

asked Jan 1, 2017 at 7:21

18 votes

7 answers

3k views

Beautiful Theorems and what constitutes as beautiful [closed]

asked Apr 23, 2014 at 7:24

13 votes

1 answer

3k views

Puzzle: Give an algorithm for finding a frog that jumps along the number line

asked Dec 30, 2014 at 20:01

11 votes

4 answers

494 views

Calculate $\sum_{n=1}^{\infty}(\frac{1}{2n}-\frac{1}{n+1}+\frac{1}{2n+4})$

asked Oct 31, 2014 at 18:59

11 votes

4 answers

471 views

Calculate $\int_{0}^{1}\frac{\arctan(x)}{x\sqrt{1-x^2}}dx$

asked Jun 14, 2014 at 19:07

11 votes

1 answer

2k views

Why is Erdős–Szekeres theorem sharp?

asked Dec 3, 2013 at 19:48

10 votes

3 answers

2k views

riddle that involves elementary geometry

asked Dec 10, 2014 at 22:26

10 votes

4 answers

9k views

Are all Nonograms / griddlers uniquely solvable?

asked Oct 10, 2015 at 14:50

10 votes

5 answers

4k views

Is polar coordinates enough to prove that a limit exists

asked Feb 23, 2016 at 22:33

9 votes

2 answers

137 views

Idea is correct, proof lacks rigor, coefficient of $t$ in $\det(I+tA)$

asked Feb 26, 2018 at 1:30

9 votes

2 answers

18k views

Consistency of matrix norm — $\| A x \|_2 \leq \| A \|_{F} \| x \|_2$

asked Apr 3, 2014 at 17:14

8 votes

4 answers

295 views

$\iint_{\mathbb R^2} \frac{dx \, dy}{1+x^{10}y^{10}}$ diverges or converges?

asked Jun 18, 2014 at 17:07

8 votes

1 answer

1k views

Prove or disprove - Newton's method convergence in higher dimensions

asked Feb 20, 2015 at 16:04

8 votes

1 answer

4k views

Combinatorics - Catalan numbers recursive function proof by induction help

asked Nov 19, 2013 at 22:04

7 votes

1 answer

11k views

Multivariable calculus - find derivative using implicit differentiation

asked Apr 4, 2014 at 17:35

7 votes

3 answers

100 views

prove simple binomial sum, combinatorics

asked May 23, 2016 at 21:50

6 votes

1 answer

7k views

Why does matrix multiplication represent linear transformation compositions?

asked Oct 3, 2015 at 16:46

6 votes

3 answers

437 views

Cool property of the number $24$

asked Apr 5, 2014 at 23:23

6 votes

2 answers

315 views

$\int_{0}^{\infty}\int_{1}^{\infty}\frac{x^2-y^2}{(x^2+y^2)^2}dxdy$ diverges?

asked May 24, 2014 at 19:10

6 votes

3 answers

677 views

optimal way to approximate second derivative

asked May 26, 2014 at 21:08

6 votes

1 answer

21k views

Is the integral of the sum really the sum of the integrals?

asked Feb 15, 2015 at 20:17

6 votes

1 answer

465 views

Shannon Entropy, prove $H(Wx)=H(x)+\log|\det W|$

asked Dec 29, 2014 at 20:47

6 votes

2 answers

100 views

Find $S=\frac{1}{2}+\frac{3}{2^2}+\frac{5}{2^3}+\frac{7}{2^4}+...+\frac{2n-1}{2^n}+...$

asked Oct 30, 2014 at 11:31

6 votes

5 answers

662 views

Find the $2013$th power of a given $3\times 3$ matrix

asked Nov 24, 2013 at 9:57

6 votes

3 answers

146 views

Show that $\sum_{k=2012}^{n} 2^k\binom{n}{k} = \Theta(3^n)$

asked Dec 17, 2013 at 17:48

5 votes

2 answers

9k views

How do I find upper triangular form of a given 3 by 3 matrix??

asked Nov 30, 2013 at 20:03

5 votes

4 answers

438 views

Is there an invertible matrix that transposes?

asked Dec 8, 2013 at 21:05

5 votes

4 answers

7k views

Relations between matrices and linear transformations, diagonalization. [duplicate]

asked Nov 12, 2013 at 17:06

5 votes

4 answers

5k views

$A$ is a symmetric real matrix. Show that there is $B$ such that $B^3=A$

asked Dec 26, 2013 at 18:30

Stack Exchange Network

490 Questions

There is no smallest infinity in calculus?

Generating multivariate normal samples - why Cholesky?

Beautiful Theorems and what constitutes as beautiful [closed]

Puzzle: Give an algorithm for finding a frog that jumps along the number line

Calculate $\sum_{n=1}^{\infty}(\frac{1}{2n}-\frac{1}{n+1}+\frac{1}{2n+4})$

Calculate $\int_{0}^{1}\frac{\arctan(x)}{x\sqrt{1-x^2}}dx$

Why is Erdős–Szekeres theorem sharp?

riddle that involves elementary geometry

Are all Nonograms / griddlers uniquely solvable?

Is polar coordinates enough to prove that a limit exists

Idea is correct, proof lacks rigor, coefficient of $t$ in $\det(I+tA)$

Consistency of matrix norm — $\| A x \|_2 \leq \| A \|_{F} \| x \|_2$

$\iint_{\mathbb R^2} \frac{dx \, dy}{1+x^{10}y^{10}}$ diverges or converges?

Prove or disprove - Newton's method convergence in higher dimensions

Combinatorics - Catalan numbers recursive function proof by induction help

Multivariable calculus - find derivative using implicit differentiation

prove simple binomial sum, combinatorics

Why does matrix multiplication represent linear transformation compositions?

Cool property of the number $24$

$\int_{0}^{\infty}\int_{1}^{\infty}\frac{x^2-y^2}{(x^2+y^2)^2}dxdy$ diverges?

optimal way to approximate second derivative

Is the integral of the sum really the sum of the integrals?

Shannon Entropy, prove $H(Wx)=H(x)+\log|\det W|$

Find $S=\frac{1}{2}+\frac{3}{2^2}+\frac{5}{2^3}+\frac{7}{2^4}+...+\frac{2n-1}{2^n}+...$

Find the $2013$th power of a given $3\times 3$ matrix

Show that $\sum_{k=2012}^{n} 2^k\binom{n}{k} = \Theta(3^n)$

How do I find upper triangular form of a given 3 by 3 matrix??

Is there an invertible matrix that transposes?

Relations between matrices and linear transformations, diagonalization. [duplicate]

$A$ is a symmetric real matrix. Show that there is $B$ such that $B^3=A$