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  • Member for 9 years, 5 months
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23 votes
4 answers
14k views

Factorial of infinity

22 votes
1 answer
27k views

$\sin(x)$ infinite product formula: how did Euler prove it?

15 votes
4 answers
8k views

Bernoulli numbers generating function

15 votes
1 answer
3k views

Apéry's constant ($\zeta(3)$) value

15 votes
1 answer
5k views

Zeta function zeros and analytic continuation

15 votes
2 answers
789 views

Why should I consider the components $j^2$ and $k^2$ to be $=-1$ in the search for quaternions?

12 votes
5 answers
6k views

The 'sine and cosine theorem' - formulas for the sum and difference

7 votes
3 answers
1k views

Do you feel comfortable with integral u-substitution? (reverse chain rule)

7 votes
3 answers
5k views

Derivation for hypergeometric distribution formula and comparsion with Bernoulli formula

6 votes
1 answer
967 views

Derivative $\Delta x$ and $dx$ difference

5 votes
1 answer
253 views

Is this notation good for the chain rule derivative?

4 votes
2 answers
2k views

Bernoulli polynomials properties

4 votes
6 answers
13k views

Proof of the substitution rule for integrals for the indefinite case

4 votes
3 answers
206 views

$\Omega$ open connected of $\mathbb{R}^N$ and $K\subset \Omega$ compact, then $c u(x) \le u(x')\le C u(x)$ for $u$ harmonic

3 votes
2 answers
233 views

Finding $\sup\limits_{\lambda\ge 0}\{\lambda^ke^{-a\lambda^2/2}\}$

3 votes
1 answer
208 views

$\sup_K |\partial^{\alpha}u|\le C^{|\alpha|+1}\alpha!^s$ then $u$ is analytic for $s\le 1$

3 votes
0 answers
241 views

Bernoulli formula

3 votes
0 answers
195 views

$\sin(x)$ infinite product [duplicate]

3 votes
1 answer
1k views

Sum of self power [duplicate]

2 votes
1 answer
322 views

Large numbers calculation

2 votes
2 answers
342 views

Solution for Cauchy Problem $u_t-u_{xx} = 0$ belongs to the Gevrey class of order $1/2$

1 vote
0 answers
214 views

Solution for the heat equation that doesn't belong to the Gevrey Class

1 vote
1 answer
252 views

If $u$ is a solution to the wave equation (Cauchy) then $|u(x,t)|\le A/t$ for some $A$

1 vote
0 answers
41 views

$u(x,t) = \frac{1}{\pi^{N/2}}\int u_0(x-2\sqrt{t}y)e^{-|y|^2}\ dy$, then $|u(x,t)|\le M(1+4\delta t)^{-N/2}e^{-\delta|x|^2/(1+4\delta t)}$

1 vote
0 answers
91 views

How can the method of spherical means be used to prove uniqueness of the wave equation?

1 vote
2 answers
117 views

How do a transformation 'born'?

1 vote
3 answers
121 views

$\frac{1}{1-x}$ series expansion

1 vote
2 answers
300 views

Intuitive Bernoulli numbers

1 vote
1 answer
288 views

Historical reason to define a matrix vector product the way it is

0 votes
1 answer
256 views

Historical reason to define a vector dot product the way it is