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seen Jun 18 at 21:58

Jun
2
comment If $y=x^{x^{x^{x^{x^{.^{.^{.}}}}}}}$ then how $y=x^y$?
I haven't proven that the tower converges. I proved that $(b_n)$ converges, since the OP asked me to in the comments.
May
31
comment What is the pdf of the area of a rectangle having sides $X$ and $2-X$, with X r.v. in $(0,2)$?
Try plotting a graph to see when the event $1-(X-1)^2<a$ occurs.
May
31
comment Variant on divergence theorem
@custodia Yes, in particular we can choose $\vec{k}$ to be each of the basis vectors.
May
31
comment Variant on divergence theorem
One way to show the identity is to apply the divergence theorem on $\vec{k}f$, where $\vec{k}$ is a constant vector, and noting that $\nabla\cdot\vec{k}f=\vec{k}\cdot \nabla f$, since $\vec{k}$ is constant.
May
31
comment What is the pdf of the area of a rectangle having sides $X$ and $2-X$, with X r.v. in $(0,2)$?
Find the CDF and differentiate to get the PDF.
Oct
16
comment Is it true that $\lvert \sin z \rvert \leq 1$ for all $z\in \mathbb{C}$?
The second equation should read $4i=e^{iz}-e^{-iz}$. The error carries on from there.
Sep
21
comment On the roots of $t^4-6\sqrt3t^3+8t^2+2\sqrt3t-1=0$
Excellent, thanks. For the last sentence, you mean $n=0,1,2,4$.
Mar
30
comment If i randomly select $n+1$ integers smaller that $2n$ , must there include an integer which divisible with one of the others?
I suppose negative integers are not permitted?
Feb
19
comment Conditional probability. What is the meaning of this explanation?
In other words, the solution is $\frac{1}{6}\cdot0.4$.
Feb
12
comment Probability of an event
I suspect what the question really means is that the test returns positive for .95 of the people with diabetes for .02 of the people without.
Feb
9
comment How to find more numbers like this?
If you require cubes, all such numbers are here: oeis.org/A046197.
Feb
9
comment IMO-2012 Problem 6 (Dušan Djukić, Serbia)
See artofproblemsolving.com/Forum/viewtopic.php?p=2737435.
Dec
6
comment Find variance of a normal distribution given 2 probabilites are equal
@Eric May I know which calculator you're using? You just need the function $\Phi(x)$ and the ability to plot a graph. Just plot the graph of $y=2\Phi\left(\frac Ax\right)-\Phi\left(\frac Bx\right)$ and find where it cuts the 'x-axis'. On TI calculators, $\Phi(x)$ is normcdf.
Dec
5
comment Operations for operands with powers of different bases
Not only is $5\neq 2.23^2$, there is also no point in writing it that way. In general, the most reduced form of writing rational numbers is in terms of powers of primes.
Dec
5
comment 6 Women and 5 Men number of positions problem I don't understand
A man cannot start first - there aren't enough men (try it).
Dec
4
comment How to find the solution of a function with 2 variables and find a limit involving $(3^x + 2^x)^{1/x}$
Are you sure you copied the equation of the curve correctly? $x^2+y^2=16(x^2-y^2)$ is just a pair of intersecting lines.
Dec
4
comment Combinatorics: $N$ balls of $R$ different colors into $R$ bins
Surely this will depend on the colour breakdown of the $N$ balls, i.e. how many balls there are of each colour.
Dec
3
comment Finding number of cases , arranging people around circular table
Are the seats distinct?
Dec
3
comment What are my expected final earnings?
@DavidFaux If you get $0$,$1$ or $2$ heads on your first toss, you can (and will) re-toss just once. So the amount of money you get is exactly equal to the number of heads you will get on your re-toss.
Dec
3
comment Is there a winning strategy for Scrabble?
You might want to look at this open source Scrabble move analyser: people.csail.mit.edu/jasonkb/quackle