# Search results

2. ### Mathematica Case function in Mathematica

Does anyone familiar with a convenient way in Mathematica to define a case function such as: y(x)=\left\{\begin{array}{c} x \\ -x\end{array}\begin{array}{c} x>0 \\ x<0\end{array} \right. ? Thankes, Omri
3. ### Scalar field as quantum operator.

Thank you all! It was very helpful.
4. ### Scalar field as quantum operator.

Hallo, I was wondering what is the physical significance of scalar field \Phi (x) as an quantum operator. \Phi (x) have canonical commutation relation such as [ \Phi (x) , \pi (x) ] so it must be an opertor, thus what are his eigenstates? Thanks, Omri
5. ### Editing equations in Mathtype

thanks bobm, the thing is i have word 2007 and mathtype 6 and i can't find the MathType tab in Word's Ribbon. is there anything else i can do?
6. ### Editing equations in Mathtype

Hallo everyone, I have a word document full of equations in Mathtype and I added a new equation which I wrote in different size and style. Does anyone know how I can change the old equations (not one by one) so their properties (size, style) would be exactly as those of the new equation...
7. ### Free electron model

Hallo, i would like to know why do we use the term free electron gas instead of Plasma? aren't both the same? thanks, Omri
8. ### Soap Bubble and surface tension

I read to today that soap bubbles explodes due to surface tension regardless of other forces experienced on the bubble. how does surface tension does that? does it "drive" the bubble to go larger until it explodes? Thanks, Omri
9. ### Defination of E D and P fields

i recommend on Arthur F kip book: http://www.amazon.com/dp/0070853819/?tag=pfamazon01-20 Omri
10. ### Sphere velocity in liquid-fluid mechanics

Homework Statement a rigid sphere of radius R and density \rho1 mooving (linearly) inside a liquid of densiity \rho0 and viscosity constant \mu the liquid is in hydrostatic equilibrium under gravitational field g. what is the velocity of the sphere after a very long time assuming Raynolds...

12. ### Why a pair is exciton?

thanks, that was very helpful :smile: omri
13. ### Why a pair is exciton?

hey, i cant understand what is the motivation of defining pair of hole and electron as a single particle, exciton. thus they seem to have distinct motion and space. so why still we treat them as excitons?
14. ### Defination of E D and P fields

Hallo everyone, in electrostatic we have a linear realation between E D and P, i do understand that P is related to the polaryzation density but what about E and D? which of those represent the overall field?
15. ### MATLAB Calling matrices from workspace to For loop in MATLAB

Thanks, It's working now, i really appreciate it! Omri
16. ### MATLAB Calling matrices from workspace to For loop in MATLAB

Hallo, I have matrices on my workpace and i need to take the first element from each one and produce new vector. In other words, i have the matrices D1,D2,D3....D36 on my workspace and by using a For loop i want to generate a new vector: d=[D1(1,1) D2(1,1)...D3(1,1)]. does anyone know...
17. ### C/++/# Random function in c++

Hallo, I'm looking for a Random function in c++. i tried to use in the function rand()% but it does not generate a truly uniformly distributed random number in the span (since my span is large. 100000*100000). in other word it dosent generate a random number in equal probabilty in lage...
18. ### MATLAB Vectors in matlab

thanks for ypur responde, i understand what you are saying, but is there a loop or other command that generate 3 vectors a_1, a_2, a_3 from the matrices A?
19. ### MATLAB Vectors in matlab

Hallo, I have a 3*3 matrices in matlab: A=[ 1 2 3; 4 5 6; 7 8 9]; and i wont to accept a vector from each colume in an easy way, i.e. a1=1 2 3 , a2=4 5 6 , a3=7 8 9 so i tried to wrote: for i=1:3 a_i=A(:,i); end but i only the last vector, a3=7 8 9... if anyone have...
20. ### Semiconductors and light effects

A piece of Semiconductor is irradiated by light, will the light effects on resistivity be intensified or reduced if the temprature is increased? why?
21. ### Y(lm) function

as i said, sorry for the first massage i had some problems with Latex. I have just edit a new one Omri
22. ### Y(lm) function

I'm sorry; I have some difficulties with Latex... I have attached Pdf with my question on finding Y(1-1) (l=1,y=-1). Thanks, Omri
23. ### Continuous partial derivatives

Hallo, What is the condition for partial derivatives to be continuous (if I have function f(x,y))? Thanks, Omri
24. ### Rolle's Theorem

Hallo. If we consider Rolle's Theorem: "If f is continuous on [a, b], differentiable in (a,b), and f (a) = f (b), then there exists a point c in (a, b) where f'(c) = 0." Why do we need to state continuity of f in interval and differentiability of f in open segment? Why can't we say f...
25. ### Simple harmonic oscilator

sorry for that... i ment that if i have a potential with maximum points does the velocity is zero there?
26. ### Simple harmonic oscilator

yes, but what about the non stable equilibrium point (maximum points)? thanks omri
27. ### Simple harmonic oscilator

Hallo, Does the velocity i simple harmonic oscillator is zero in equilibrium points? if it's true how does it make sense with the fact that i suppose to get a maximum kinetic Energy in those points (stable ones) i would realy appriciate if someone could clear this issue for me...
28. ### Uncertainty in simple harmonic oscilator

Hallo, Why can we assume (in the case of simple harmonic occilator) that at the maximum momentum ,pmax, we can evluate pmax=\Deltap? Thanks, Omri
29. ### W=z^n- transformation in complex space

Hallo, When i regard complex function, Why does the transformation w=zn don't "conserve" angels when z go to infinity? Thanks Omri
30. ### Interior points

thank you for your comments, I'm sorry but the statement (as i guess you already assume) was: "The set Q has no interior points, and neither does its complement, R\Q" thanks Omri