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Data scientist and math blogger.


Nov
19
answered Taking Seats on a Plane
Nov
16
revised Why is $1^{\infty}$ considered to be an indeterminate form
added comment about \infty^0
Nov
16
comment Why is $1^{\infty}$ considered to be an indeterminate form
Thanks, Chandru. (Now maybe one of these days I'll get to teach calculus again.)
Nov
16
revised Why is $1^{\infty}$ considered to be an indeterminate form
fixed notation
Nov
16
answered Why is $1^{\infty}$ considered to be an indeterminate form
Nov
15
answered A root? Or two roots?
Nov
14
comment Questions on a Test
The sum of k exponentials is gamma-distributed, as you've pointed out. But as k goes to infinity, the gamma distribution, appropriately rescaled, converges to normal.
Nov
11
comment What is the combinatoric significance of an integral related to the exponential generating function?
Is there some reason to expect that this integral has combinatorial significance?
Nov
11
comment Expected number of steps before three counters reach N modulo 2N at the same time
The answer is "obviously" proportional to N<sup>3</sup>, the size of the state space, but I can't say more off the top of my head.
Nov
10
comment Parenthesis vs brackets for matrices
Bey, I'm teaching game theory this semester. Lots of matrices. You bet I'm using parentheses. (And I even use parentheses in things I write up in LaTeX, like solutions to the homework, just for consistency.)
Nov
10
answered Parenthesis vs brackets for matrices
Nov
7
answered Product of all elements in an odd finite abelian group is 1
Nov
7
comment Probability of cumulative dice rolls hitting a number
The related question mathoverflow.net/questions/18282/… at mathoverflow might be of interest. The consensus in that discussion was that there wasn't a "nice" explicit formula (although there is the partial-fraction formula that Moron gives below) but that these probabilities are easy to compute recursively.
Nov
3
comment Intuitive explanation of the difference between waves in odd and even dimensions
This is called Huygens' principle. See mathpages.com/home/kmath242/kmath242.htm although I wouldn't call the explanation there "intuitive".
Nov
2
answered Positive integers $k = p_{1}^{r_{1}} \cdots p_{n}^{r_{n}} > 1$ satisfying $\sum_{i = 1}^{n} p_{i}^{-r_{i}} < 1$
Nov
1
comment Proof of $P(X < x) = F(x−)$
Hi, Josh! I have to keep saying hi so that this comment is long enough.
Oct
31
comment Asymptotic difference between a function and its binomial average
I agree that logarithmic growth is what you need. The "binomial average" of $f(n)$ should be about $f(n/2)$.
Oct
30
comment Does Stirling's formula give the correct number of digits for $n!\phantom{}$?
Portuguese is not that hard to read, at least if you know French and/or Spanish, which are languages more commonly known to speakers of English. That being said, the meta.mathoverflow discussion on posting in non-English posts: meta.mathoverflow.net/discussion/142/nonenglish-posts. (The consensus there was that posts in all languages should be allowed, but there would probably be few non-English posts.)
Oct
30
answered Generalization of cos: is this function known?
Oct
30
comment Does Stirling's formula give the correct number of digits for $n!\phantom{}$?
From Mathoverflow: mathoverflow.net/questions/19170/… and mathoverflow.net/questions/19086/number-of-digits-in-n