376 reputation
17
bio website
location Universidade de São Paulo, Brazil
age 29
visits member for 1 year, 9 months
seen Mar 21 '13 at 20:24

I am currently a post-doc at the Physics department at the University of Sao Paulo. My interests are in Statistical Physics, stochastic processes and magnetism. More importantly, I really value simple and solid explanations to important problems in any science.


Aug
16
accepted Solving for specific entries in a Lyapunov Equation
Aug
16
accepted Approximate solution for the root of a non-linear function
Aug
14
comment Solving for specific entries in a Lyapunov Equation
Actually, I have been looking at the web and haven't yet found a method for solving the eq. for B. Any ideas on where to look?
Aug
14
comment Solving for specific entries in a Lyapunov Equation
Wow, this is great. Thank you! I'll start testing this idea right away and post some results as soon as they come out.
Aug
9
comment Solving for specific entries in a Lyapunov Equation
@dato, Sorry I don't understand.
Aug
9
comment Solving for specific entries in a Lyapunov Equation
The solution of the Lyapunov equation, $R$, will be symmetric and positive definite (it is actually a covariance matrix). What I can prove is that $C$ is anti-symmetric ($C^\text{T} = -C$)
Aug
9
asked Solving for specific entries in a Lyapunov Equation
Jul
30
awarded  Critic
Jul
28
comment Partial Fractions Expansion of $\tanh(z)/z$
Yeah. Probably. Hehe. It's just that I never know how to deal with sums in any other way than comparing it to other sums. Again, thank you for the answer J.M.
Jul
28
answered Self-study resources for basic probability?
Jul
28
accepted Partial Fractions Expansion of $\tanh(z)/z$
Jul
28
comment Partial Fractions Expansion of $\tanh(z)/z$
@jm this is great; does all such formulas rely on manipulating other known products and sums? Isn't there, for instance, a Fourier transform or generating function approach (or something...)? Again, thank you for the support.
Jul
27
comment Approximate solution for the root of a non-linear function
Let $F_\pm(t) = e^t (g \cos(\omega t-\phi) \pm b)$. The first point, $t_0$ say, is computed from either $F_\pm(t_0) = F(0) \mp \alpha$, where $\alpha$ is a positive constant. From there one the roots are computed sequentially as above.
Jul
27
revised Approximate solution for the root of a non-linear function
Updated the instability aspect of the problem.
Jul
27
comment Approximate solution for the root of a non-linear function
Thank you all very much for the support and thank you @LeonidKovalev for the bounty.
Jul
27
asked Partial Fractions Expansion of $\tanh(z)/z$
Jul
27
accepted Variation of a simple random walk
Jul
26
comment Approximate solution for the root of a non-linear function
Yes Mr. Badwaik. I want the first $t_1$ after $t_0$.
Jul
25
awarded  Scholar
Jul
25
accepted Book suggestion for linear algebra “2”