Recent content by HassanEE

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    Question about electric generators

    You need to go back to first principles, and you'll see why everything you've proposed becomes awful complicated. Charge exists everywhere, but for practical purposes, it isn't useful whatsoever unless it is moving nicely in a predictable manner, with amplitude and direction. Your typical...
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    Question about electric generators

    Static is just accumulated charge producing an electric field that want to be discharged (like when you touch the doornob in a cold winter). There is energy in there, but it's discharged instantaneously as soon as it finds a path to do so, and that's not useful in any way shape or from. Unless...
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    Why is there no fibre for microwave (or other) frequencies?

    An optical fiber is actually a waveguide. I'm quoting Cheng's Fundamentals of Engineering Electromagnetics "A type of waveguide of particular importance for optical frequencies consists of a very thin fiber of a dielectric material, typically glass, cladded with a sheath . . . Such optical...
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    Question about electric generators

    Windadct, I was under the impression that most generators are asynchronous. I guess I was mistaken. Bararontok, if by electrostatic generator you mean DC generators, I can tell you about the last power generation, transmission, & distribution conference I attended. There was a lot of babble...
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    Question about electric generators

    That's a good question, but you're missing a teeny-tiny detail. Large generators have to be excited by the grid and that's why they operate at the same voltage. They return energy in the form of current, while maintaining the same voltage. You want to think of the step-up/down transformers as an...
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    What is the difference between global and local maxima and minima?

    If I may interject here. Take a look at this graph http://www.stat.purdue.edu/images/Research/Profiles/velocityReal2.jpg you'll see many humps (maxima). All the humps are local maxima in the sense that they are all peak values at their respective intervals. However, the one at around 0.58 is...
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    What is the difference between a differential equation and a derivative?

    The difference is that a derivative, in an abstract sense, is a mathematical operation you apply onto a function/variable (like logarithms, exponentiation, square roots, etc). A differential equation is an equation that just-so-happens to contain derivatives. Here's a simple example: we call x5...
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    Simple complex power: why is e^( i (2*Pi*n*t)/T ) not 1?

    Hello Aziza, In case you're still skeptical, here's a couple of examples. If you had something like: eiπ/3 = (eiπ)1/3 = (ei/3) = 1/2+sqrt(3)/2. Then the identity applies, but take a look here: (e2πi)i = 1i =/= e-2π = e2∏ii The identity does not hold, and you can't really guess when and where...
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    What is the axis label for the fourth dimension?

    Fourth dimension is frequently time--denoted with letter t.
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    When can interchange sum and integral

    The reason you can interchange is not because the variables are independent but because the operations are; that is, the integration and the summation.
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    Method of Proving Euler's Formula?

    I see where HallsofIvy is getting at. Before you go ahead and find the Fourier series, you have to show periodicity. For f(x) to be periodic it must satisfy f(x+T)=f(x) for all t. If f(x)=eix then eix=ei(x+T). At this point you will not be able to proceed unless you used Euler's formula (or...
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