User draks ... - Mathematics Stack Exchange

39 votes

What is a negative number?

answered Jun 17, 2015 at 7:59

23 votes

Funny identities

answered Nov 16, 2011 at 11:57

23 votes

Real life examples of commutative but non-associative operations

answered Dec 15, 2013 at 20:58

15 votes

Accepted

Finding sum of factors of a number using prime factorization

answered Jun 26, 2012 at 10:03

15 votes

Is it possible to elementarily parametrize a circle without using trigonometric functions?

answered Oct 7, 2016 at 21:46

12 votes

What does this "subset" symbol mean?

answered Jan 17, 2012 at 9:49

12 votes

Proving that $\sum\limits_{i=1}^k i! \ne n^2$ for any $n$

answered Mar 8, 2012 at 8:49

11 votes

Accepted

Interpolating the primorial $p_{n}\#$

answered Jul 24, 2012 at 19:47

10 votes

What are the properties of a prime number?

answered Jan 4, 2012 at 13:42

10 votes

Example of a conjecture/theorem which required an entirely new idea to prove

answered Dec 16, 2012 at 13:08

10 votes

Accepted

What is the sum of $\sum\limits_{i=1}^{n}ip^i$?

answered Aug 8, 2012 at 7:21

9 votes

Sum of all elements in a matrix

answered Jul 30, 2012 at 12:10

9 votes

Accepted

Properties of sum of real symmetric, positive semi-definite matrices

answered Oct 4, 2012 at 12:58

9 votes

Algorithm(s) for computing an elementary symmetric polynomial

answered Oct 9, 2012 at 19:47

8 votes

Accepted

Do there exist infinitely many primes $p$ such that $a^{p-1}\equiv 1$ $\text{mod } p^2$ for fixed a?

answered Jun 21, 2012 at 9:07

8 votes

Solution af a system of 2 quadratic equations

answered Jul 26, 2012 at 10:05

8 votes

Accepted

Are these two facts related?

answered Nov 24, 2012 at 12:55

8 votes

Inverse of circulant matrices

answered Nov 23, 2015 at 14:17

7 votes

Accepted

A mathematical way for defining the $\operatorname{Floor}$ and $\operatorname{Ceiling}$ functions

answered Apr 2, 2014 at 13:54

7 votes

Fibonacci trick and proving it.

answered Apr 3, 2014 at 5:29

7 votes

Accepted

About the Continuum Hypothesis

answered Mar 26, 2012 at 13:35

7 votes

Taylor Expansion of Error Function

answered Mar 28, 2012 at 10:58

6 votes

Accepted

2x2 Matrices and Differences of Fractions

answered Jul 23, 2012 at 12:28

6 votes

Accepted

Composition of two polynomials

answered Jul 23, 2012 at 14:45

6 votes

Accepted

Limit of a sequence involving root of a factorial: $\lim_{n \to \infty} \frac{n}{ \sqrt [n]{n!}}$

answered Jul 17, 2012 at 12:29

6 votes

Accepted

Derivative of sinc function

answered Jul 17, 2012 at 20:47

6 votes

Can you provide me historical examples of pure mathematics becoming "useful"?

answered Jan 17, 2013 at 11:03

6 votes

Limit for sequence with $e$-function

answered Nov 29, 2013 at 16:52

6 votes

Are there connected, planar graphs of size $N$ with minimal degree $\left( N−2 \right)$ for any $N \in \mathbb{N}$?

answered Aug 29, 2013 at 19:46

6 votes

Rational Roots of Riemann's $\zeta$ Function

answered Jan 6, 2013 at 23:22

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469 Answers

What is a negative number?

Funny identities

Real life examples of commutative but non-associative operations

Finding sum of factors of a number using prime factorization

Is it possible to elementarily parametrize a circle without using trigonometric functions?

What does this "subset" symbol mean?

Proving that $\sum\limits_{i=1}^k i! \ne n^2$ for any $n$

Interpolating the primorial $p_{n}\#$

What are the properties of a prime number?

Example of a conjecture/theorem which required an entirely new idea to prove

What is the sum of $\sum\limits_{i=1}^{n}ip^i$?

Sum of all elements in a matrix

Properties of sum of real symmetric, positive semi-definite matrices

Algorithm(s) for computing an elementary symmetric polynomial

Do there exist infinitely many primes $p$ such that $a^{p-1}\equiv 1$ $\text{mod } p^2$ for fixed a?

Solution af a system of 2 quadratic equations

Are these two facts related?

Inverse of circulant matrices

A mathematical way for defining the $\operatorname{Floor}$ and $\operatorname{Ceiling}$ functions

Fibonacci trick and proving it.

About the Continuum Hypothesis

Taylor Expansion of Error Function

2x2 Matrices and Differences of Fractions

Composition of two polynomials

Limit of a sequence involving root of a factorial: $\lim_{n \to \infty} \frac{n}{ \sqrt [n]{n!}}$

Derivative of sinc function

Can you provide me historical examples of pure mathematics becoming "useful"?

Limit for sequence with $e$-function

Are there connected, planar graphs of size $N$ with minimal degree $\left( N−2 \right)$ for any $N \in \mathbb{N}$?

Rational Roots of Riemann's $\zeta$ Function