User NovaDenizen - Mathematics Stack Exchange

41 votes

How to generate a random number between 1 and 10 with a six-sided die?

answered Jun 6, 2015 at 22:09

11 votes

The series of reciprocals of the integers that do not contain 9 in their decimal representation

answered Oct 6, 2014 at 15:36

11 votes

Sum of a power series $n x^n$

answered Jan 22, 2014 at 16:01

11 votes

Can you create non transitive dice for any finite graph?

answered Jan 24, 2016 at 7:36

10 votes

Accepted

Unreachable rubik cube positions.

answered Feb 13, 2014 at 2:04

8 votes

How to derive the formula for the sum of the first $n$ odd numbers: $n^2=\sum_{k=1}^n(2k-1).$

answered Dec 14, 2013 at 15:52

7 votes

Accepted

Fibonacci number ending with given sequence of digits

answered Jul 22, 2014 at 15:55

6 votes

Accepted

Prove that $\forall a,b,c,d\in \mathbb{R}\,$, $(a^2-b^2)(c^2-d^2)\leq(ac-bd)^2$ and equalities hold if and only if $ad=bc$.

answered Mar 14, 2015 at 11:47

6 votes

Accepted

How to define an affine transformation using 2 triangles?

answered Jan 5, 2015 at 17:28

6 votes

Accepted

Rubik's Cube Thistlethwaite Four Phase Algorithm

answered Jul 17, 2015 at 0:36

5 votes

Is the set $\left\{\frac{1}{n} \mid n = 2,3,4,\ldots\right\}$ a countable infinite set?

answered Oct 13, 2014 at 21:20

5 votes

Primes dividing $11, 111, 1111, ...$

answered Nov 6, 2014 at 20:55

5 votes

Show that for every prime $p$, there is an integer $n$ such that $2^{n}+3^{n}+6^{n}-1$ is divisible by $p$.

answered May 8, 2015 at 5:16

5 votes

Accepted

Look at the following infinite sequence: 1, 10, 100, 1000, 10000, . . ..

answered Sep 20, 2014 at 2:29

5 votes

Arrangement of the words SUCCESS in which the consonants appear in alphabetic order

answered Sep 4, 2014 at 18:08

5 votes

Accepted

Calculate $\sin(x)$, $\cos(x)$, and $\tan(x)$ without calculator

answered Oct 5, 2014 at 4:50

5 votes

Can I approximate sine and cosine without derivatives?

answered Feb 23, 2014 at 17:53

4 votes

Gcd number theory proof: $(a^n-1,a^m-1)= a^{(m,n)}-1$

answered Feb 17, 2014 at 1:09

4 votes

How to prove $\sum_{n=0}^\infty \frac1{n!}=e\ $?

answered Jun 12, 2014 at 13:38

4 votes

Why is $\lim_{x \to 0} \frac{\sin(2x)}{8x} = \frac{1}{4}$

answered Jun 30, 2014 at 1:27

4 votes

Accepted

Simplifying $\frac{1/(\frac{1}{z_1}(1-t)+\frac{1}{z_2}t) - z_1}{(z_2 - z_1)}$

answered Mar 3, 2015 at 22:37

3 votes

Accepted

Sum of digits of all 4-digit numbers divisible by 7

answered Nov 5, 2014 at 19:37

3 votes

Accepted

Reduction of 3-SAT to 3-COLOR

answered Nov 21, 2014 at 15:44

3 votes

Accepted

Number of Fibonacci series that contain a certain integer

answered Sep 29, 2014 at 0:22

3 votes

$3 \times 3$ Rubik's cube scrambling question

answered Aug 1, 2014 at 17:14

3 votes

How find the matrix $K$ such $AKB=C$

answered Jul 8, 2014 at 4:17

3 votes

Accepted

Where is the interior of the polygon?

answered Jul 8, 2014 at 14:16

3 votes

Accepted

What's the opposite of damping?

answered Aug 11, 2014 at 16:07

3 votes

Independence in card deck

answered Feb 13, 2014 at 1:31

3 votes

Accepted

Representing $-2.5$ as a floating point number

answered Feb 23, 2014 at 18:10

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181 Answers

How to generate a random number between 1 and 10 with a six-sided die?

The series of reciprocals of the integers that do not contain 9 in their decimal representation

Sum of a power series $n x^n$

Can you create non transitive dice for any finite graph?

Unreachable rubik cube positions.

How to derive the formula for the sum of the first $n$ odd numbers: $n^2=\sum_{k=1}^n(2k-1).$

Fibonacci number ending with given sequence of digits

Prove that $\forall a,b,c,d\in \mathbb{R}\,$, $(a^2-b^2)(c^2-d^2)\leq(ac-bd)^2$ and equalities hold if and only if $ad=bc$.

How to define an affine transformation using 2 triangles?

Rubik's Cube Thistlethwaite Four Phase Algorithm

Is the set $\left\{\frac{1}{n} \mid n = 2,3,4,\ldots\right\}$ a countable infinite set?

Primes dividing $11, 111, 1111, ...$

Show that for every prime $p$, there is an integer $n$ such that $2^{n}+3^{n}+6^{n}-1$ is divisible by $p$.

Look at the following infinite sequence: 1, 10, 100, 1000, 10000, . . ..

Arrangement of the words SUCCESS in which the consonants appear in alphabetic order

Calculate $\sin(x)$, $\cos(x)$, and $\tan(x)$ without calculator

Can I approximate sine and cosine without derivatives?

Gcd number theory proof: $(a^n-1,a^m-1)= a^{(m,n)}-1$

How to prove $\sum_{n=0}^\infty \frac1{n!}=e\ $?

Why is $\lim_{x \to 0} \frac{\sin(2x)}{8x} = \frac{1}{4}$

Simplifying $\frac{1/(\frac{1}{z_1}(1-t)+\frac{1}{z_2}t) - z_1}{(z_2 - z_1)}$

Sum of digits of all 4-digit numbers divisible by 7

Reduction of 3-SAT to 3-COLOR

Number of Fibonacci series that contain a certain integer

$3 \times 3$ Rubik's cube scrambling question

How find the matrix $K$ such $AKB=C$

Where is the interior of the polygon?

What's the opposite of damping?

Independence in card deck

Representing $-2.5$ as a floating point number