1,437 reputation
823
bio website about:blank
location Berlin, Germany
age 19
visits member for 3 years, 3 months
seen Apr 14 at 22:54

I'm a highschool student from Germany interested in functional programming, especially Haskell.


Jan
17
comment Question about a lemma on continuity
@Arturo Sorry. That was a translation mistake. In German, one says "stetig" to say "continuous". stetig and steady are false friends...
Jan
8
comment Given the cartesian coordinates of four points, how to calculate the interection of two lines they form?
@J.M. Oh yeah. That looks good. THank you! BTW, is there a solution that use the $r,\vartheta$ representation instead?
Jan
8
comment Given the cartesian coordinates of four points, how to calculate the interection of two lines they form?
@J.M. Of course. This possibility is ruled out.
Dec
2
comment Defining division by zero
@picakhu You are going to run into problems when calculating limits. Just consider $\lim_{n\to0}\frac{2n}n$. Using your method, one gets $\frac{\infty_0}{\infty_0}=1$, while one gets $\frac21=2$ using the definition of limits.
Nov
13
comment How to convert $\sqrt{\frac{5}{3}}$ to $\frac{\sqrt{15}}{3}$?
@Max ${5\over3}\to{15\over9}$
Nov
13
comment How to convert $\sqrt{\frac{5}{3}}$ to $\frac{\sqrt{15}}{3}$?
BTw, you can use LaTeX makeup by starting with an \$ and ending with another \$, for instance $\sqrt{\frac{5}{3}}$ becomes $\sqrt{\frac{5}{3}}$.
Nov
11
comment A lemma of convergence
@André: yes. We already proved that.
Nov
8
comment The Mathematics of Tetris
That's an interesting question! I don't see any special reason for this, though.
Nov
1
comment Prove the identity $ \sum\limits_{s=0}^{\infty}{p+s \choose s}{2p+m \choose 2p+2s} = 2^{m-1} \frac{2p+m}{m}{m+p-1 \choose p}$
Hm... I recall that or a similar identity from Concrete Mathematics... maybe I find it again.
Oct
24
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
@Gortaur: Well, that's not that difficult. You just need to find a geometrical interpretation of sine and cosine.
Oct
23
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
Sorry for that.
Oct
23
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
Thank you very much. I know that proverb, but I really wasn't able to find that out on my own.
Oct
23
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
Hm... But now, how to prove that $\cos$ is continuous? (Read the question!)
Oct
23
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
Okay. I had a look at the link Yuval provided. That proof works. Anyway, thanks for the effort.
Oct
23
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
But how to prove that $\sin x<x<\tan x$?
Oct
23
comment How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
@mixedmath Sorry. That was indeed a typo.
Oct
12
comment Finding the number of newspapers
@Ramana It seems so, though I can't prove it.
Oct
10
comment A Tricky Limit: $(1 - \frac{c}{n}\log n )^{1-n}$
Wolfram Alpha says, $\lim_{n\to\infty}(1-\frac cn\log n)^{1-n} = \infty$...
Oct
10
comment Probability of a random $n \times n$ matrix over $\mathbb F_2$ being nonsingular
The number even appears on oeis.org as A048651
Oct
10
comment Probability of a random $n \times n$ matrix over $\mathbb F_2$ being nonsingular
It seems that there is something called $q$-Pochhammer symbol, such that $\prod^n_{k=1}(1-2^{-k})=(1/2;1/2)_n$. It seems that this actually converges: $(1/2;1/2)_\infty=0.2887880950866\dots$