1,687 reputation
926
bio website fuz.su/~fuz
location Berlin, Germany
age 20
visits member for 3 years, 11 months
seen yesterday

I am a student of computer science and mathematics at the Humboldt University of Berlin.


Apr
12
comment Solving a scrambled $3 \times 3 \times 3$ Rubik's Cube with at most 20 moves!
I would suggest looking on Wikipedia And also here
Apr
6
comment Please help me to show, that $(\ln x)'=\frac1 x$
Thank you. Great answer.
Apr
6
comment Please help me to show, that $(\ln x)'=\frac1 x$
@Arturo Magidin: Thank you very much.
Apr
6
comment Please help me to show, that $(\ln x)'=\frac1 x$
@quanta: Please don't cheat. I want to get an answer I can use to understand the derivation. But anyway, thanks for the definition.
Apr
6
comment Please help me to show, that $(\ln x)'=\frac1 x$
Ah... Okay. And how to show, that $\lim_{\delta\to\infty}\ln\left(1-\frac1{x\delta}\right)^\delta = x^{-1}?$
Apr
6
comment Please help me to show, that $(\ln x)'=\frac1 x$
@Fabian: In our school, we are doing l'Hôpital in grade 11, I don't want to wait that long ;)
Apr
6
comment Please help me to show, that $(\ln x)'=\frac1 x$
@Arturo Magidin: Yes. Sorry. Got confused by myself.
Apr
4
comment Common algorithm with an order of Θ(2^n)
Hm... I'm not a mathematician. Thank you.
Mar
29
comment Find a closed form for this sequence: $a_{n+1} = a_n + a_n^{-1}$
That's still only an asymptotic.
Mar
8
comment How to prove that a polynomial of degree $n$ has at most $n$ roots?
@Moron: Okay. Thank you for this.
Mar
8
comment How to prove that a polynomial of degree $n$ has at most $n$ roots?
@Moron: It's a part of the fundamental theorem. Consider this question as answered.
Mar
8
comment How to prove that a polynomial of degree $n$ has at most $n$ roots?
@Moron: I'm not (yet) in university. This isn't homework. Just asking this as a part to proof my last question. I'm asking this because I didn't knew, that this is a fundamental theorem of algebra.
Mar
5
comment How to prove the equality $\sum_{j=0}^n (x)^j (-1)^{n-j} \left\{{n \atop j}\right\} = x^n$?
Is your $(x)^j$ the same as $x^\overline{j}?$
Mar
5
comment Equality of polynomials: formal vs. functional
@Harry Stern: Yes :)
Mar
5
comment Equality of polynomials: formal vs. functional
@Qiaochu Yuan $a_k, b_k \in \mathbb{C}$
Mar
4
comment Equality of polynomials: formal vs. functional
Sorry, formulated the question wrong.
Mar
4
comment Equality of polynomials: formal vs. functional
@Jason DeVito: $a_k$ and $b_k$ are just coefficients. They're independent of $x$.
Feb
23
comment Three non-coplanar lines in the 3D-space always have a fourth one that intersect them all?
This proof is the easiest to understand for me. Thank you.
Feb
13
comment Does the formula $\sqrt{ 1 + 24n }$ always yield prime?
Uhhh... That's difficult. Thanks for this link.
Feb
12
comment Does the formula $\sqrt{ 1 + 24n }$ always yield prime?
Changed. I thought it's very difficult or impossible to find a prime generating function which only yields primes. Can you give me an example?