the_candyman's user avatar
the_candyman's user avatar
the_candyman's user avatar
the_candyman
  • Member for 11 years, 4 months
  • Last seen this week
36 votes

Ways to write "50"

32 votes
Accepted

Is it acceptable to have a fraction in an eigenvector?

18 votes
Accepted

Is there a clean way to write down this "product" of a vector and a matrix? Does it have any interpretation?

16 votes

Why does $ \operatorname{Var}(X) = E[X^2] - (E[X])^2 $

14 votes
Accepted

Why are natural numbers countable?

11 votes

I found this odd relationship, $x^2 = \sum_\limits{k = 0}^{x-1} (2k + 1)$.

8 votes
Accepted

Find $\det(A^{2}+A^{T})$ when eigenvalues are $1,2,3$

8 votes
Accepted

Finding the original ODE using a solution

7 votes

Let $A_{n\times n}$ be a real matrix. Is it true that $I+A^TA$ is invertible?

7 votes
Accepted

$\lim_{x\to\infty} \frac{x}{\sqrt{9x^2 +x} -3}$

7 votes
Accepted

How to differentiate this negative power?

7 votes
Accepted

How many $N$ digits binary numbers can be formed where $0$ is not repeated

7 votes

An almost Fresnel integral

6 votes
Accepted

If $X$ and $Y$ are independent exponential then $\{\min(X,Y)>z\}$ and $\{X<Y\}$ are independent?

6 votes
Accepted

How is $x^2$ related to $x^Tx$

6 votes

To find whether $a$ is a prime number

6 votes

How does one rotate a function?

6 votes
Accepted

Mean perimeter for random triangle inscribed in the unit circle

6 votes
Accepted

From system of coupled ODEs to separable ODE

6 votes
Accepted

Showing $\frac{(x^2+1)(y^2+1)(z^2+1)}{xyz}\geq 8$

5 votes
Accepted

Is $f(x)=\begin{cases}x \ \text{if } x\in [0,1),\\3-x \ \text {if} \ x \in [1,2]\end{cases}$ continuous from $[0,2]$ to $[0,2]$? Yes/No

5 votes
Accepted

show that $\frac{1}{2}\cdot \sum\limits _{k=0}^{\infty }\:\frac{k^2}{k!}\:=e$

5 votes

Proving that $\sum_{n=1}^{\infty}\frac{(-1)^{n+1}}{n^{2}}=\frac{\pi^{2}}{12}$

5 votes

Finding mixed Nash equilibria in continuous games

5 votes

(Infinite) Nested radical equation, how to get the right solution?

5 votes

Why this :$\sum\limits_{n=0}^{\infty}(0)=0$?

5 votes
Accepted

Convergence of a series with radicals: $\sum\limits_{n=1}^{\infty}\frac{\sqrt{n+2}-\sqrt{n+1}}{n}$

5 votes
Accepted

What's wrong with this "proof" that $\frac {de^x}{dx} \neq e^x$?

5 votes
Accepted

Calculate the coordinates of the third vertex of triangle given the other two and the length of edges in the cheapest computational way

5 votes
Accepted

Convergence of the sequence $a_{k+2} = \sqrt{a_{k+1}}+\sqrt{a_k}$

1
2 3 4 5
16