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Aug
9
comment How do I compute such theoretical expectations?
What is the structure of the graph on which the random walk is being performed?
Aug
9
comment Finding standrad deviation $\sigma$
did you check that $1/3$ of the cartons can be reserved fresh for $22+$ days?
Aug
9
comment Prove formally that if $\lim_{n\to+\infty} a_n = +\infty$ then $lim_{n\to+\infty}b_n = +\infty.$
Write down what it means formally when a sequence diverges and use the fact that bs are larger than the as.
Aug
7
comment Fourier transform of $e^{-at^2}= \frac{1}{\sqrt{2a}}e^{\frac{-w^2}{4a}}$
@CameronWilliams so what should be done when the same person is asking the same question again within 2 hours of each try?
Aug
7
comment terminology for a “forward flow” type of random digraph
@Emisor I think he means if $i<j$ then there will be an edge with probability $p$. He is working on random graphs...
Aug
6
comment The equivalence principle and experiments concerning it?
I don't think this is the place for debate questions either...
Aug
5
comment Path continuous but not continuous
What are your thoughts on the problem?
Aug
5
comment my computation of a real integral still has an imaginary number in it,
Could you please put the integral you are trying to compute into the problem?
Aug
3
comment Is it possible to make a linear reformulation?
@R.Dj.M. converting products to sums isn't an easy thing to do, unfortunately
Aug
3
comment Is it possible to make a linear reformulation?
@R.Dj.M it is a standard technique in integer programming, which is the heart of the branch and bound method.
Aug
2
comment Elegant solution for $\int {\frac{\cos(y)}{\sin^2(y)+\sin(y)-6}}dy$
Using MathJax makes your answers much more readable. Please learn it and thank you for contributing to the site.
Aug
2
comment A question on inequality and differentiation of logarithms
Related to the reverse of Jensen's inequality: en.wikipedia.org/wiki/Jensen%27s_inequality
Jul
31
comment Solve differential equation
@Jason yes, indeed
Jul
31
comment Solve differential equation
i think you get $\sin x + \ln |\sec x|$, and must carry the absolute value unless you restrict yourself to the interval where $\cos x \ge 0$...
Jul
31
comment What does it actually mean if a cost function is differentiable?
@Karnivaurus some derivatives are hard to analytically express :)
Jul
31
comment Polynomial Interpolation and Data Integrity
When you say you evaluate $f$ at $x$, do you mean that $f:\mathbb{R} \to \mathbb{R}$ is a 1-D polynomial and $y_i=f(x_i)$ or that $f:\mathbb{R}^n \to \mathbb{R}^n$ is a vector-valued polynomial which takes $n$ inputs and returns $n$ outputs?
Jul
30
comment In what conditions a quadratic function has an integer value of $f(x)$ where $x$ is also an integer?
$y \in \mathbb{Z}$ iff $a,b,c \in \mathbb{Z}$
Jul
30
comment Is this (funny) combinatorial optimization problem NP-hard ? (cutting numbers and placing them in urns)
lower bound seems to come from the idea that if everything divides evenly you put exactly $$m = \frac{\sum b_i}{nC}$$ in each cell. The problem with that is you may have some numbers $b_i < m$ which would mean you cannot use $m-b_i$ from each such cell. So you "waste" $\sum (m-b_i)^+$ in total...
Jul
30
comment Is this (funny) combinatorial optimization problem NP-hard ? (cutting numbers and placing them in urns)
another idea: perhaps $$x = \frac{1}{nC} \sum_i b_i$$ can be used to derive a lower bound (I think it is $xC$), which you can improve by adding $\sum (x-b_i)^+$ to it.
Jul
29
comment If independent r.v. converge in probability to a constant, do they converge almost surely?
Do you mean that each element of the sequence be independent, or it is a series of independent terms, which is converging?