# Recent content by Eynstone

1. ### Proving something is bounded

I'm not sure what you are trying to prove - is it given that u,v are harmonic & uv>=0 ?
2. ### Stochastic differential equation problem

This will turn into a standard equation of the type dv/dt=kv+ noise after a change of variable. For some general methods for solving SDEs, I hope the following link will be of much help - http://math.berkeley.edu/~evans/SDE.course.pdf
3. ### Bounded Lebesgue integrals

Proceed by indirect method : if the integral over E is strictly > e ,then the integral over E_k should also exceed e for sufficiently large k.
4. ### Solving Uxx - Uy - Ux =0

Does the equation look familiar if you put x+y=t ?
5. ### Does anyone know the name of this type of map

How about calling this a 'hyperinvolution'?
6. ### Commuting derivative/Integral (not FTC or Leibniz)

I don't see any simple relation between the two.Although L is periodic, its second order derivatives may not be so.
7. ### What to read after Understanding Analysis

Have you come across Korner's ' A Companion to analysis'? I find it a good second course, even after having studied Rudin's & Apostol's books. Separate textbooks on complex analysis & on differential geometry would help , as these have much special attributes. An overview of books...
8. ### Brownian Motion 1 (birth-death)

The value of c follows from the varience of the process.( Note that this has to be a 1-dimensional random walk).
9. ### Need help w/ Fibonnaci and Golden Ratio proof

Just use the formula for nth fibonacci number.
10. ### Fixed Point Iteration Convergence

Try to find bounds on x_(n+1) in terms of x_n ,y_n ( for instance, when it's less than x_n).
11. ### Oscillator with and without damping - Need help please

It won't be simply the sum of the two. It will consist of alternate pieces of the graphs of the two. We must consider the time intervals in which x>0 & x<0 separately.
12. ### Two general questions about differential equations.

Have you tried 'Differential Equations' by Simmons? It's a good book & contains many problems in physics. For a course in PDEs, you must be familiar with calculus of several variables & a little functional analysis.
13. ### What is the physical meaning of curvature?

The curvature of potential energy is definitely related to distribution function, but the dependence is weird.I can't give any physical meaning to curvature which might suit the dependence.
14. ### Interesting contour integral

Let a+ib =c^2, so that the integrand has poles at +-c.Integrate along a semicircle which contains a part of the real axis and loops around +-c.
15. ### Lie derivative with respect to anything else

I can't think of a definition of the lie derivative with respect to a covector off my head. However, we may talk about the lie derivative with respect to a totally contravariant tensor.We could define it as the tensor product of component-wise lie derivatives. Such a quantity could be another...