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  1. J

    How to prepare for a math quickness/accuracy pre-interviews?

    Hello, I am applying for some jobs that have pre-interview tests. Here is one description: This is for a finance job, and I am an electrical engineering major with a pretty high gpa. So I obviously have a solid math background, but what should I expect from these kinds of tests? How...
  2. J

    Easy Circuit Question

    Is the resistance of this circuit 10 ohms? http://img75.imageshack.us/img75/9229/littlecircuitro8.jpg [Broken] I can't prove anything to myself since the resistors aren't in parallel or series. I do notice that the potential at the top of the right side resistor is the same as at the...
  3. J

    Probability - Independence Question

    I'm trying to get the idea of independent events well grounded in my mind, but I'm having some difficulty. First of all, what would a venn diagram for independent events look like? I know you have the two events intersecting, and the intersection is equal to the product of the probabilities...
  4. J

    MATLAB Just bought MATLAB

    I just bought MATLAB because it is absolutely required at the university I will be attending in the fall. While I've only given MATLAB a quick overview, it seems that it's probably not something I would be able to use for writing papers. It also doesn't look very efficient for quick graphing...
  5. J

    LaTeX Best Latex Editor?

    What's a good freeware latex editor? I've been trying to install LEd, but it's not going smoothly, so I don't want to waste anymore time if it's not worth it. Any suggestions?
  6. J

    Schools What do you do in Grad school?

    O.K. This question shows just how ignorant I am about things academic, but what do people working on a PhD do? And how long does it take to get your PhD? I'm mainly interested in knowing about a PhD in mathematics. Here are my questions: 1)Do you take only classes that relate to math...
  7. J

    Divergence Problem

    This problem has me stumped: If r = (x^2 + y^2)^{1/2}, show that div \left( \frac{h(r)}{r^2}(x \vec{i} + y \vec{j}) \right) = \frac{h'(r)}{r} My trouble is with mixing the polar coordinates with the position vector. If I write the above as div \left( \frac{h((x^2 +...
  8. J

    Understanding Divergence Graphically

    I'm trying to get a handle on seeing whether a vector field (in the x-y plane for simplicity) has zero divergence at a point or is divergence free altogether. I'm having some trouble with this. The way I am thinking about it is to mentally draw a little box around my point and then see...
  9. J

    Dilemma: Engineering vs. Math - Help me Decide!

    Dilemma: Engineering vs. Math -- Help me Decide! Hello everyone. I'm in a weird position. First a little background: I'm 27 years old. I dropped out of high school when I was 16. I returned to school two years ago and have done very well at my local community college. And now (this is...
  10. J

    Amperian Loop

    If you know the net current enclosed in an amperian loop is zero, when can you conclude that the field at every point on the loop is zero? Here's my actual problem. Part a), I'm pretty sure I did fine (B= u0*I/(2*pi*r)). Part b) I'm guessing that B equals 0 at any radius r greater than c...
  11. J

    When is field interaction instantaneous?

    I think I understand how signals can be sent by field disturbances, and that the disturbance is propogated at the speed of light. Now, I was wondering about the case where a stationary field is already set up and you place a test charge in that field. Does that charge move instantaneously...
  12. J

    Image distance / focal length relation

    Let O be the object, L be the lense, I be the image, and S be a screen for projecting an image. The lens can be placed anywhere between O and S. Let f be the focal length of the lense. Prove that for an image to be clearly formed on screen S, OS > 4f must be true. A figure of a "too...
  13. J

    A book to spark the imagination?

    Does anyone know of any good books that are about engineering/engineering history that are really good at motivating and sparking the imagination of a prospective engineer? I have loved pure mathematics for a few years, and I realize I've read many books on its history, its "big names", etc. I...
  14. J

    I need help with an entropy integral!

    I know the final and initial temperatures of .259kg of aluminum. Specific heat of almuninum is 900 J/(kg*K). The aluminum is cooled from 373K to 333.45K. I need to find the entropy change. This is what I did: let c = specific heat, m = mass, T = final temperature Q = cm(T - 373) <=> Q =...
  15. J

    Heat from Entropy & Temp

    I am given the number of moles of an ideal monotomic gas. I am also given a chart with a graph of temperature plotted as a function of entropy. One of the questions is: find the heat that was transferred to the gas. How do I find that? I thought about saying: dS = dQ/T <=> dQ = T...
  16. J

    Momentum and the pressure of an ideal gas. Easy Question.

    My book (Halliday, 6th ed: Section 20-4), uses the momentum of the individual molecules in a gas to derive the pressure of the gas. They imagine the molecules hitting a wall. I'm a little rusty on my memory of conservation of momentum, so this equation is confusing me a bit: (delta)px = (-mvx)...
  17. J

    Engineering Physics

    I was looking at Cornell's website describing its engineering physics program, and it appealed to me A LOT. I've had a hard time choosing an engineering field, and this seems like it's for me. I also would love to study the more advanced mathematics which EP requires. It also seems to give me...
  18. J

    Age Discrimination?

    Is it very risky for a 27 year old to begin study in an aerospace engineering program? If I get a b.s. in 3 or 4 years, would age discrimination be a problem in getting an aerospace job? Or any engineering field for that matter? Thanks.
  19. J

    I need advice.

    I really need some help on deciding what I am going to do as far as a career is concerned. The problem is I am 27 years old, and I'm in a bit of a panic that I'm running out of time. For anyone that is interested and would be willing to give me some pointers, I would really be grateful. I...
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