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"I would never die for my beliefs because I might be wrong."

-- Bertrand Russell


Apr
19
comment Set difference of real numbers and rational numbers
There is no problem here. It's a definition.
Apr
18
comment Mathematics needed in the study of Quantum Physics
Since you seem to be russophone, do you know any nice websites where I can download pdf's of freely available texts on math and/or physics in Russian?
Apr
13
comment Get the Nth term of a sequence 1,2,4,7,13,24…
The characteristic polynomial of the recurrence is exactly the characteristic polynomial of the matrix. It doesn't make a difference what method you choose.
Apr
12
comment Proof about complex exponential function forming an infinite dimensional vector space
This is the complex exponential. It is not bijective at all.
Apr
12
comment Separate Into Real and Imaginary Parts
A more handy approach would be to use $\tan^{-1}x=\frac{1}{2i}\ln(\frac{1+ix}{1-ix})$.
Apr
9
comment Financial Mathematics - Security Market Line and CAPM
I think this would fit better on quant.SE.
Apr
9
comment Which number is larger and Why? 1.7 or 1.73205
Are you maybe from a culture that reads from right to left?
Apr
7
comment s-shaped reverse logistic curve
Just literally do what you're saying: reverse the logistic. The inverse function of the logistic is $\ln \frac{x}{x-1}$.
Mar
30
comment Physical shapes you can't simulate using mathematical functions
Sure, but I think the point is that as long as you're being flexible about how you define your object in terms of a function, there's no limit on the shapes you can desribe in those terms. The question is: is it interesting?
Mar
30
comment Physical shapes you can't simulate using mathematical functions
@tom: $F:\mathbb{R}^2\to\mathbb{R}^3:(u,v)\mapsto (\cos u \cos v, \cos u \sin v, \sin u)$. The sphere is given by the set of image points of the function.
Mar
28
comment Why is $\pi$ so close to $3$?
What do you mean close? It's also close to 0 and 100.
Mar
27
comment Why this ODE isn't Bernoulli?
You can solve it by separation of variables.
Mar
27
comment Deriving a conservative form of the Cauchy Equation?
Note that they take the divergence of a tensor field, which is a vector.
Mar
27
comment Accumulated sum of integer random variables
Uniformly distributed?
Mar
23
comment Mill's Inequality on normal distribution
Where's the inequality?
Mar
19
comment Geometric meanings of hyperbolic cosinus and sinus
@Frank: In many languages, we do call them "cosinus" and "sinus". He might not have known how to write them in english.
Feb
5
revised Define variable value - General Math
edited tags
Feb
5
reviewed Approve suggested edit on Given the sum of two exponential random variables, what is the conditional distribution of one of them?
Jan
31
awarded  Nice Answer
Jan
29
comment Why does $\frac{1 }{ 99989999}$ generate the Fibonacci sequence?
It can't generate the full sequence since it would be non-repeating.