# Search results

1. ### Cryptography with the NSA?

Well how it works is you take "classes" and are taught the material while you work. It's a few years training program so I'd essentially end up with a masters level understanding of the subject before I really became a 'cryptanalyst'. I'm currently looking at actuarial stuff because that...
2. ### Cryptography with the NSA?

Thanks for the responses; yes I realize that the NSA has a terribly long clearance process, and that even if I got a COE now in July I wouldn't have a job by next March with them. I wasn't aware that I could apply before I had a degree and just say "I will have degree by X time" Knowing that...
3. ### Cryptography with the NSA?

So here is my situation: I am planning on graduating March 2011 with a B.S in Mathematics, as well as a B.S. in Physics. My interest in physics has waned greatly, and my desire to go to grad school for either subject is non-existent right now. I took a look at the NSA, as I heard they hire...
4. ### Schools Relearning Math Before Grad School

I am currently a math/physics major who is almost done with his mathematics degree (I am a junior but I did much math and should be able to complete my degree in just three years + one quarter versus the normal four). However, I will still be taking another year or two to complete my physics...
5. ### Getting to the speed of light

No, you wouldn't. The specifics of your example don't really matter. At low speeds you use what is called "Galilean Relativity": the idea that you can add up or subtract speeds. If you are in a car going 75 MPH relative to the ground, and a car passes you going 80 MPH relative to the ground...
6. ### Integration By Substitution It's Been A While

Ah, I got it, I think. If I use the u-substitution you suggest, I get du=\frac{1}{\sqrt{x^2+z^2}}-\frac{x^2}{(x^2+z^2)^{3/2}}dx, which, getting a common denominator yields: \frac{z^2}{(x^2+z^2)^{3/2}}. So \frac{du}{z^2}=\frac{dx}{(x^2+z^2}dx My integral is then just \frac{\lambda...
7. ### Integration By Substitution It's Been A While

Sure thing. I'm trying to find the electric field at an arbitrary distance z above a straight line segment, where the arbitrary distance z is measured above one of the endpoints of the line segment. Relevant Equations: We are given that the electric field of a line charge is \frac{1}{4...
8. ### Integration By Substitution It's Been A While

Homework Statement It's been god knows how long since I've had to use integration by substitution. I've totally forgotten it. I am trying to integrate to solve for the value of an electric field at a given point. The integral I am trying to solve is...
9. ### Angular Acceleration (I don't see HOW I can be wrong?)

My friend in introductory physics came to me for help today. He has a test on angular momentum, acceleration etc. I figured, with me in upper-division physics courses, I'd be able to help him out. Well, I guess I was dead wrong. In half an hour I couldn't figure out a SINGLE THING. I don't...
10. ### Angular Momentum vs Latus Rectum

Homework Statement There is a shuttle following a circular orbit around a planet. At some point P in the orbit, the shuttle fires thrusters causing the speed at that point to increase. I am supposed to a) find the angular momentum, gravitational force at the point P, centripetal acceleration...
11. ### Time Dilation/Proper Time Question

(This isn't a homework problem, I'm struggling with this concept) My professor today was talking about time dilation. He stated that a clock that does not move in the observers point of view (a stationary clock) is, in that observer's viewpoint: a proper time. Thus, an observer on Earth will...
12. ### Motivation In my Number Theory Class…

How long should I go at these proofs before I realize they're a lost cause? I worked on this fibonacci sequence one for several hours over the course of a few days, and in the end, someone else just ended up doing the problem on the board. I'll have to rearrange office hours with my...
13. ### Motivation In my Number Theory Class…

I'm sure that for many of you this class is old news; but I just started elementary number theory this summer and, as much as I love the challenge of the course, and doing these proofs; I feel like an amateur boxing Mike Tyson here. These things are chewing me up and spitting me out. Granted I...
14. ### How to study 12+ hours per day without hurting your

I have to agree with everyone here when I say: studying 10-12 hours a day is way too much time. Not only is it wasteful to study that long (not to mention to try it in one sitting), it takes away every other aspect of your life. You need to make time for socializing and exercise. Look, my...
15. ### Theist -> Atheist

Science and the notion of God are not mutually exclusive. However, if the only point of your God is to explain natural phenomena, he becomes more and more unnecessary with more and more discoveries.
16. ### Theist -> Atheist

Seems like we're straying a bit into ontological statements. I believe that there is an area inbetween 100% denial and 100% belief (and this is not necessarily 50/50. When I deny the existence of, say Pegasus, it's because I have an idea of what someone has in mind when they say it, and I know...
17. ### Theist -> Atheist

Hurkyl, I as a person deny that God exists — the two statements you quoted me on are true. However, they are not part of my argument that I am making here. The argument I am making here is simple, and I've stated it time and time again: experience alone is not enough of a justification to...
18. ### Theist -> Atheist

If you want to get into strict logical statements, population-based arguments are invalid as well. As I stated earlier, reasoning from natural experience to supernatural existence is invalid because there is no logical correlation between natural and supernatural. These are two entirely...
19. ### Theist -> Atheist

I suppose my wording should have been a bit clearer. I am just inductively reasoning (myself) that God is another invalid experience, just like hypnogogic imagery. However, my point was not that everyone should follow my lead, and reject the existence of God for that one reason. My point...
20. ### Theist -> Atheist

I think both you and Ivan didn't quite get my point. My point was not that, because some experiences are invalid that ALL are invalid — it is simply that because some experiences are invalid, other human experiences (when taken alone) cannot be concluded to be evidence for the existence of a...
21. ### Theist -> Atheist

But there is no real link between human experience (natural) and the conclusion (supernatural). The logical relationship between experience and God is too weak to be a justifiable reason to call denying the God concept an "act of faith". At best we can conclude that human beings have similar...
22. ### What causes natural electromagnetic fields?

Well, I just learned in my EM class that what sustains the EM wave is fact that changing electric and magnetic fields continually produce one another; that is; an electric field that changes produces a changing magnetic field, and vice versa.
23. ### Self-propagating wave question

I'm currently reading about EM waves in my physics course, but there is something that is not clear to me. I know, from Maxwell's equations, that a changing electric field produces a magnetic field and a changing magnetic field likewise produces an electric field. However, it seemed from my...
24. ### Proving The Continuous Theorem for Sequences

I'm following you and it looks like I'll be proving a limit at a point, but I'm still stuck with how we can relate a_n to f(a_n), and L to f(L). If I can somehow extract the a_n and the L from the f, I could do it...again, thanks for the help so far and sorry I'm still not quite getting what to...
25. ### Proving The Continuous Theorem for Sequences

Hmm, I must not be seeing it... I get that it's going to follow the basic form of a proof. For all epsilon > 0, there exists an N such that, for all n>N, then |f(a_n)-f(L)|<epsilon. The N is more than likely going to be some integer part of some number plus one. I get how all that works...
26. ### Proving The Continuous Theorem for Sequences

Well that's the thing; I thought I could just approach it nicely, but the concepts seem to be two different things; it's as if I want to prove a finite limit at infinity. There is a proof I thought was similar to it, in the notes he gave us. However, I fleshed out a few epsilon delta...
27. ### Proving The Continuous Theorem for Sequences

Homework Statement 4.8 Show the following continuous theorem for sequences: if a_n \rightarrow L and f is a real valued function continuous at L, then bn = f(a_n) \rightarrow f(L). Homework Equations No real relevant equations here. Just good old proof I'm thinking. The Attempt at a...
28. ### Converging Sequence

Ah thx quasar; I shoulda thought of rationalization. I need to remember that everytime I see a square root... When I meant "logical way" AKG, I meant that, just by looking at the equation, we can't conclude that 1/x is bigger always. I had to look at a calculator. I have to justify my choice...
29. ### Converging Sequence

Homework Statement Determine whether each of the sequences converges or diverges. If it converges, find its limit. Explain with sufficient details each claim. Homework Equations (k) a_n=\sqrt{n^2+1}-n The Squeeze Theorem (If b_n<a_n<c_n, and both \displaystyle\lim_{x\rightarrow\infty}a_n...
30. ### Parallel Plate Capacitor Force

The problem is: Consider a parallel-plate capacitor with plates of area A and with separation d. Find F(V), the magnitude of the force each plate experiences due to the other plate as a function of V, the potential drop across the capacitor. Express your answer in terms of given quantities and...