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1414
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location Spain , Basque Country , Bilbao
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visits member for 2 years, 9 months
seen 13 hours ago

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 :)


Jun
26
comment Proving $\left\| \frac{\vec{v}}{\|\vec{v}\|}\right\| =1$, $\vec{v}\ne \vec{0}$
your expression is NOT a vector since a vector divided by an scalar is just another vector
Jun
26
comment Multiplication $ H\times P(1/x) $ in sense of distributions
Cauchy's principal value en.wikipedia.org/wiki/Cauchy_principal_value
Jun
26
comment Gelfand Shilov vol 1. question: finite part of an integral
sorry i forgot 'm' is a real number and $ s \to 0 $ , here the parameter 's' plays the role of a zeta regulator so the integral is convergent for big 's' and after the calculations we take the limit s --->0
Jun
24
comment Mellin transform of digamma function
i have used RAMANUJAN MASTER THEOREM and it is much more easier and faster however i aked if this can be obtained by another methods.
May
27
comment Logarithmic Equations
take the 3/4 power in both sides $ (5x+2)= 16^{3/4}=8 $ (use calculator) :) then $ 5x=8-2 $ and $ x=6/5 $
May
25
comment Summation with factorial terms (involving Laguerre polynomials)
rewrite $ x^{k } $ as a linear combination of Laguerre polynomials $ L_{m} (x) $ and use the orthogonality property $ \int_{0}^{\infty} L_{m}(x)L_{n}(x)exp(-x)dx =0 $
May
24
comment numerical approximation to logarithm
OK you are right perhapsh i should use this expression plus a power series involving teh difference $ln(x+1)-ln(x) $
May
23
comment numerical approximation to logarithm
so my expression should be $ ln(x)= x\int_{0}^{1} \frac{dt}{1+xt} $
May
20
comment How to find inverse of the function $f(x)=\sin(x)\ln(x)$
you CAN ALWAYS invert the function numerically , try mathwolframalpha wolframalpha.com/input/?i=%5Cinv%7Bsin%28x%29ln%28x%29%7D
May
18
comment Closed form for n-th anti-derivative of $\log x$
kurims.kyoto-u.ac.jp/~kyodo/kokyuroku/contents/pdf/1692-02.pdf
May
10
comment functional equation involving $ f(x/k) $
what does 'mathematica softwary' say ??
May
2
comment Differential Equation $y'=4|y|^{3/4}, y(0)=0$
takning integration with respect to x , since $ y=y(x) $ then we have the implicit relation $ 4x+C=|y|^{1/4} $ applying the condition $ y(0)=0 $ we get 4.0+C= |y(0)|^{1/4}=0 $ so $ C=0 $
May
1
comment Discontinuity and riemann integrability
the fractional part function is periodic with period one so $ {ax} $ is periodic $ 1/a$ for each 'a'. discontinuities are $ 1/n $ for n=1,2,3,4,5....
Apr
15
comment A cohomological statement equivalent to the Riemann Hypothesis
what differntial operator is he using ?? :) i mean you need a self adjoint operator to get the Riemann zeros as eigenvalues
Apr
12
comment Inverse Laplace Transform of zero
for any constant $ L^{-1}{C}= C\delta (x) $ if $ c=0 $ we have $0 \delta (t) =0 $ except for the case $ t=0 $
Apr
4
comment Name of $a*b=c$ and $b*a=-c$
isn't this a dot product algebra .. vectorial or dot product :)
Mar
29
comment Spectrum of the Hill Operator $L(y)= -y''+ v(x) y $
it is semiclassical WKB method :) to recover the potential
Mar
17
comment First order ODE proof
oh sorry :) , no there is by definition the MOST GENERAL first order differential equation
Mar
17
comment First order ODE proof
this is just the DEFINITION of first order differntial equation in the most general case although perhaps it should be $ a(x) y' (x)+b(x)y(x)+c(x)=d(x) $ all the first order linear differential equation are of this way
Mar
16
comment $ \sum_{n=2}^\infty \frac{1}{n^3(n^3+1)}. $
use Euler Maclaurin summation formula en.wikipedia.org/wiki/Euler_Maclaurin