2,856 reputation
1619
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location Spain , Basque Country , Bilbao
age
visits member for 3 years, 2 months
seen Nov 26 at 13:24

i got a degree on Physics and have several ideas on my own , unfortunately i do not have a physics sponsor :) in order to get an investigation grant :)


Apr
28
comment Mathematicians ahead of their time?
FOURIER invented the general method but i think that euler and bernoulli had used the fouire method to the solution of the string problem :D
Apr
28
comment Mathematicians ahead of their time?
RAMANUJAN and EULER .. Euler invented things like Borel transform FOurier analysis , Laplace transform and many other ideas which were studied hundred years after
Apr
28
comment Ordinary Differential Equations ODEs Solve the Initial Value Problem
$ e^{Mt}=1+Mt+\frac{t^{2}M^{2}}{2}+\frac{t^{3}M^{3}}{6}+..$
Mar
29
comment Why is $\zeta(s)\neq0$ for $\operatorname{Re}(s)=0$?
PRIME NUMBER THEOREM: riemann zeta function has no zeros of the form $ 1+it$ for real t therefore from the functional equation the riemann zeta function has no zeros of the form $ 0+it $
Mar
23
comment laurent series of a function defined by an integral
and for some $ |x| > 1 $ i mean an asymptotic Laurent series valid as $ x \to \infty $ thanks
Mar
23
comment laurent series of a function defined by an integral
assume all that you need :D let us suppose taht teh function can be defined for complex 'x' and so on
Mar
23
comment laurent series of a function defined by an integral
well assume that for every $ x >0 $ the integrals F(X) and H(X) exists :D
Mar
23
comment laurent series of a function defined by an integral
$ g(t) $ is smooth with no poles so the integral exists for every 'x' since there are no poles in the integrand
Mar
19
comment Real roots plot of the modified bessel function
OK thanks in fact i managed to prove that the roots of the function (smooth part) was about $ \frac{ \sqrt{E}}{2\pi}log(\frac{\sqrt{E}}{2\pi e}) $ that's why i thought that the zeros would be related
Mar
15
comment A variational problem with a lagrangian , what is the lagrangian?
THANKS a lot could yuou help me with other problems i have about variatonal calculus :D i must prove 20 exercises but i have only solved 4 :D
Feb
26
comment Help in differentiating a complicated function
$D(f(X)g(X))=f'(x)g(x)+f(X)g'(x) $ apply this to your 2 produc t and remeber the minus sign before epsilon
Feb
20
comment minimal surface from a variational problem
i have donwloade the book and in example 8.1.2 they put only the Euler lagrange equation i put in my question they do not explicitly evaluate the mean curvature of the surface
Feb
20
comment minimal surface from a variational problem
of course but i know would need the curvature equation in $ R^{n} $ to see that the vanishing of Euler lagrange equation is the vanishing also from the mean curvature in n-dimension
Feb
20
comment minimal surface from a variational problem
io know i should compare my Euler lagrange equation with the differential equation of the mean curvature am i right ? where could i find more hitns ?
Feb
20
comment minimal surface from a variational problem
i found this problem on Evans partial differential equations chapter 8 books.google.es/books/about/… chapter 8 problem 12 :)
Feb
18
comment A variational problem with a lagrangian , what is the lagrangian?
shouldn't this be the term $ e^{f(x)}$ instead ?= in both cases ??
Feb
18
comment A variational problem with a lagrangian , what is the lagrangian?
thank you RObert :D wehn i have enoguht poitn to vote i will give you a point thanks again
Feb
18
comment Solve $y'(t) = \dfrac{1}{1+ty}$
wolframalpha.com/input/…
Feb
18
comment Solve $y'(t) = \dfrac{1}{1+ty}$
i suggest to define a new function $ u(t)=ty(t) $ to see what happens
Feb
13
comment Find solution for the following system: $x'=y^3-4x$ , $y'=y^3-y-3x$
you know $ y-x=f(t) $ for some function now you should replace this identity inside your equation :D