Alexandre Halm's user avatar
Alexandre Halm's user avatar
Alexandre Halm's user avatar
Alexandre Halm
  • Member for 9 years, 6 months
  • Last seen more than 4 years ago
22 votes

Largest "leap-to-generality" in math history?

15 votes
Accepted

Can a continuous real function take each value exactly 3 times?

12 votes
Accepted

How to prove that $ \sum_{k=1}^{n-1} \frac{1}{1-e^{2 \pi i k/n}} = \frac{n-1}{2}$?

11 votes

Why rationalize the denominator?

9 votes

What is the intuition behind summability kernel and convolution?

9 votes

Examples of mathematical discoveries which were kept as a secret

8 votes

How can you prove that the square root of two is irrational?

7 votes
Accepted

Solving $(f(x))^2 = f(\sqrt{2}x)$

6 votes
Accepted

lim$_{n\rightarrow \infty}\int _{-\pi}^\pi f(t)\cos nt\,dt$

6 votes
Accepted

Derivability of a function with an infinity of zeroes

4 votes

How to prove $\sum_{k=1}^{n}k\binom{n}{k} = n2^{n-1}$

4 votes

Finding inverse of a function $h(x) = \frac{1-\sqrt{x}}{1+\sqrt{x}}$

4 votes
Accepted

Can a function $f:\mathbb{R^n} \mapsto \mathbb{R^m}$ where $n<m$ be surjective?

4 votes

Prove that if $\sum |a_{n}|$ converges then $\sum a_{n}^{2}$ converges

4 votes
Accepted

$t^2$ can't be a solution to the differential equation

4 votes
Accepted

Functions $f: \Bbb Q_{+} \to \Bbb Z$ such that $f(\frac{1}{x}) = f(x)$ and $(x+1)f(x-1)= xf(x)$

3 votes

How to integrate $\int_{\gamma}\frac{dz}{z}$

3 votes
Accepted

calculating the limit $\lim_{n\to ∞} (n+1)\int_{0}^1 x^nln(1+x)dx$

3 votes
Accepted

Find the minimum value of $ \int_0^1 (1+x^2)f^2(x)dx$

3 votes

$[0,1]$ without numbers which have the digit $8$ in them?

3 votes

Where can I find the solutions to exercises of Probabilistic Graphical Models?

3 votes

Find continuous $f$ with period $1$ such that $f(x) =\int_0^1 f(x-t)f(t) dt$

3 votes

Proof by Induction:

3 votes

Prove that $\sum\limits_{n=1}^\infty \frac{n^2(n-1)}{2^n} = 20$

2 votes
Accepted

How to calculate a changing probability situation based on possible improvement? Can this problem not be solved precisely, just estimated?

2 votes
Accepted

Cardinality of the power set

2 votes

General formula for $\sin\left(k\arcsin (x)\right)$

2 votes

Are there algorithms for solving simple functional equations?

2 votes

Prove that g is differentiable

2 votes
Accepted

Show that $\sum_{k=1}^\infty (a_k - a_{k+1}) = a_1 - l$ if $\lim_{k \to \infty} a_k = l$