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Comments:
<0> does anyone have a text to recomend for learning how to deal with partial diff. equations? I'm basically lost in my intermediate E&M cl***.
<1> hi
<0> w***up
<1> does anyone know the reason why most photodiodes are operated at a pd above -6
<1> i look all over the internet nothing...
<2> hi.
<1> hi
<0> isn't there a voltage drop of .6V for diodes, omaremad ?
<1> for?
<0> I mean, always.
<1> hmmmm its a photo diode in reverse bias
<1> not a directional diode
<0> <-out of my expertise here
<1> ok
<1> :(
<0> do YOU know by any chance of any book that does a good job explaining Partial Diff eqns, specifically solving them using Legendre Polynomials?
<1> nom im just a humble kid
<0> ditto
<3> Linkt is Griffiths not sufficient?
<1> try wikipedia
<1> or ecluidian space (nice website)
<0> dunno, haven't looked at it, microacg . all I have is Boas "Mathematical Methods in the phyisical Sciences"
<0> thanks for the website.
<0> What book is griffiths?
<3> hold 1 second
<3> http://www.amazon.com/Introduction-Electrodynamics-3rd-David-Griffiths/dp/013805326X/sr=1-1/qid=1170801353/ref=pd_bbs_sr_1/002-6891669-1806425?ie=UTF8&s=books
<4> Griffiths has written THE book on Electrodynamics.
<4> And THE book on Quantum Mechanics as well I tihnk.
<4> But I don't quite see the relevance to partial diff equations
<3> then get http://www.amazon.com/Introduction-Quantum-Mechanics-David-Griffiths/dp/0131118927/ref=pd_bxgy_b_img_b/002-6891669-1806425 yeah
<0> gee, thank you very much Arsanerit , microacg . Right now i'm using Wangsness, electromagnetic Fields.
<3> Another good book is: "Green Eggs and Ham"
<0> Sam I am?
<5> Linkt, Yep, that's his pattern - only three letter words.
<0> What the hell are Legendre Polynomials Anyway?
<0> although, on a ligher note... whats up with that variable-refractive index invisibility machine?
<6> Haven't seen it.
<0> so basically, if you had a box made of a material with a variable refractive index, you could theoretically engineer it in such a way that light were bent completelly around the material and exited as if the object weren't there. making it invisible. for some wavelenghts, at least.
<5> Well, at least for wavelenghts of photons being thrown at the material
<5> Just imagine throwing other sorts of special particles that we can extract visual information from. :)
<0> the only problem would be... whoever is inside could not see out!
<0> granted, kanzure .
<5> Linkt, not necessarily - perhaps a grey goo swarm of microcameras distributed over the environment
<5> with an internal sensor/receptor
<5> for the specific wavelengths that the data is being transmitted over
<5> and some sort of quick algorithm to re***emble the information
<5> (maybe too much of a latency in the entire process...)
<0> or basic radar, as well.
<0> radar would be good.
<5> radar does not have high quality reception to my knowledge
<5> and is not a replacement for video feeds into whatever system is "invisible"
<0> heck, if sonar is good enough for a bat to find a moth, i'm sure we could build something good too.
<5> somehow I doubt we can compare our daily behaviors, actions, etc. to those of a bat, Linkt ;)
<0> I don't know man, you should see some of the guys hanging around chicago's south side at night.
<7> anyone know where I can buy tritium phials from?
<8> tritium phials?
<9> nite
<10> jabberwalkie, are you here?
<11> evaluate the integral: [sin(sqrt(x))] / sqrt (x) my answer was -2cos(sqrt(x)). could someone check my answer please?
<12> abasinisvacant: use mbot
<12> mathematica syntax
<12> which I dont know :P
<11> yes, i've got my answer at #math
<11> @botsnack
<13> :)
<12> abasinisvacant: ok
<10> does air resistance matter if an objects velocity is 0?
<10> as in, is air resistance 0 whe nvelocity is 0?
<11> isn't air resistance completely different from velocity?
<10> im talking about when an object is at its highest point
<10> it has 0 velocity
<11> at the peak, yes
<12> well depends...normally air resistance is taken as a function like f=kv
<12> where v is velocity..so practically it does not matter
<12> but thats an approximation of course
<8> air resistance can be linear or quadratic in velocity
<12> purplepenguin: can be even trigonometrical :D
<12> depends
<12> essentially can be anything
<8> I've only had to deal with the linear and quadratic approximations m'self
<8> for projectile motion
<12> yeah... thats the common
<8> lots of Matlab approximate solving of couples diff-eq's
<8> coupled*
<12> and seems to work pretty fine in those cases..I believe
<8> cl***ical mechanics is kinda fun, I think
<12> I like better non-cl***ical hehe
<12> but yeah... it's kinda fun
<8> Lagrangian mechanics
<8> everything is so easy in some ways
<8> just find the Lagrangian and you can get the equations of motion
<12> well I actually dont even know cl***ical mechanics :P lol
<12> but I find, say QM; more interesting
<12> even when I dont know QM at all lol
<8> Feynmann did once say that no one understands quantum mechanics once
<10> lol
<8> I think I understand quantum mechanics but I don't really feel comfortable with it
<10> where did that quote end
<10> at the "mechanics" or at "once"
<12> purplepenguin: well that's very relative
<12> according to your meaning of understanding something
<12> and I dont believe feynman said that
<12> unless you can show me otherwise
<10> wow, mefistofeles is taking penguin tio town
<10> i like it
<8> at mechanics
<12> whats_in_a_name: I dont even know what you mean... lol
<12> town?..or is that down?
<12> and Im not trying to bring anyone down...just to clarify some stuff :D
<10> no, "town"
<10> its an american english expression
<8> I'm fairly sure Feynmann said that, could be wrong
<10> just google it.. if you care so much
<8> http://thinkexist.com/quotes/with/keyword/quantum_mechanics/
<12> nah I wont :P
<12> im too lazy
<8> I don't agree with Feynmann's sentiment much either
<12> and I dont really like those "american expressions"
<12> I think I can safely say that nobody understands Quantum Mechanics
<12> ahh nice
<12> and as I said..depends how do you define "understand"
<12> or "really understand"
<12> heh
<5> "What I cannot create, I do not understand." - Feynman
<5> Feynman did "succeed" in creating his own interpretative language for quantum electrodynamics, but he seemed to get stuck after that
<5> he was close, but no cigar (to add to the American statements :-p)
<5> * American expressions
<8> Feynmann diagrams and path integral formalism are supposedly important to QFT
<8> I haven't been exposed to it...yet
<12> kanzure: damn you!
<12> lol
<12> just jokin
<5> :) Yep, the path integral formulation is important - wish I understood it!
<5> I have looked at some basic path integrals in my calculus text, though have not spent the time recursively going through it to understand all of the definitions, it still interests me immensely though.
<8> The path integrals in QFT are wickedly difficult, because it is a sum over all possible paths
<8> you have to try and make some of them cancel out to get a reasonable answer
<12> yah
<12> read something about that
<12> but thats it lol
<5> purplepenguin: I have heard that many times before, "sum over the possible paths"
<5> in terms of photons that means the sum over the possible histories
<12> yeah
<5> in other words the possible routes that they travfel
<5> *travel
<5> and have been obsessed with finding out more about this interpretation
<5> what does it mean, precisely?
<12> I read that in Feynman's QED book
<8> I don't entirely understand
<5> does that mean that it is also the sum of all the possible interactions of the amplitudes of all the many, countless photons in the universe that will collide to interact with molecules and make them vibrate into more photon-related collisions etc?
<5> mefistofeles: Yeah, I read that too -- finished it one hour after the beginning of this new year. :)
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