Recent content by SALAAH_BEDDIAF

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    Integrating with Infinite boundaries

    Okay, so I have all the roots now, as these roots are very difficult to be represented by fractions, can I use the approximate roots to find the residues or will I have to use the exact value?
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    Integrating with Infinite boundaries

    so the roots of (x^4 + x^3 + x^2 + x + 1) are also the remaining roots of (x^5-1)?
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    Integrating with Infinite boundaries

    So I understand I will be evaluating this integral using Cauchy's Residue Theorem so I must find the singularities in the function, this is when (x-1)(x^4 + x^3 + x^2 + x + 1) = 0 , from (x-1) we get a singularity to be 1, but I'm having difficulty finding (x^4 + x^3 + x^2 + x + 1) to be 0
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    Integrating with Infinite boundaries

    Homework Statement Show that \int_{-\infty}^{+\infty} \frac{x-1}{x^5-1}dx = \frac{4\pi}{5}sin(\frac{2\pi}{5}) The Attempt at a Solution This is actually a piece of work from a complex analysis module (not sure if it belongs in this part of the forum or in the analysis section) I...
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    Definite Integral limit problems

    But from the substitution, wouldn't the limit of 2\pi become 0? Both points give us a value of 0 as tan(0) = tan(2\pi)
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    Definite Integral limit problems

    https://www.dropbox.com/s/06om29hdi2p6ikt/20131129_165002.jpg
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    Identifying singularities of f and classifying them

    Thanks, but on my course we don't use any sort of expansions so I'm having difficulty understanding what the expansion actually tells me, I just wanted to know if those singularities I have are just simple poles or poles of higher order.
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    Definite Integral limit problems

    \int_0^{2\pi} \frac{1}{25cos^2(t) + 9sin^2(t)}dt Substituted the variables twice and got the upper and lower boundaries to both be 0 (think i might have gone wrong there) \frac{1}{15} tan^{-1} \frac{3tan(t)}{5} with upper and lower boundaries both being 0. I know the answer is 2\pi/15...
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    Identifying singularities of f and classifying them

    Hi guys, just wanting to know if I'm doing this right. f(z) = \frac{z}{(z^2 + 4) (z^2+1/4)} Singularities of f(z) are when (z^2 + 4), (z^2 + 1/4) = 0 In this case, the singularities are \pm2i , \pm\frac{i}{2} Lets call these singularities s and s is a simple pole if \lim_{z...
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    How to Express Function f in Terms of Complex Variable z?

    Let f(x+iy) = \frac{x-1-iy}{(x-1)^2+y^2} first of all it asks me to show that f satisfies the Cauchy-Riemann equation which I am able to do by seperating into real and imaginary u + iv : u(x,y),v(x,y) and then partially differentiating wrt x and y and just show that \frac{\partial...
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    RLC Circuit Second Order Differential Equation

    [SIZE="4"]okay i got i_1 + i_2 + i = i_s (t) using the equalities v = iR = L\frac{di}{dt} = \frac{Q}{C} I got i_1 R = L \frac{di}{dt} → i_1 = \frac{L}{R}\frac{di}{dt} not too sure how to transform C\frac{dv}{dt} → LC\frac{d^2 i}{dt^2}
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    RLC Circuit Second Order Differential Equation

    I think i may have got it? here is what i have Current through resistor: \frac{1}{R} Current through inductor: \frac{1}{L} \int i\,dt Current through Capacitor: C\frac{dv}{dt} Applying kirchhoffs law i got \frac{1}{R} + \frac{1}{L} \int i\,dt + C\frac{dv}{dt} = 0...
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    RLC Circuit Second Order Differential Equation

    no I'm able to solve the equation, it's just that I'm ahving difficulty showing that the equation equals what i have given
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    RLC Circuit Second Order Differential Equation

    Homework Statement Hi there guys I am new to this forum and i have a problem with a bit of cw. It's regarding an RLC circuit. I've come up with a picture (attached) that denotes the equation. Homework Equations I know the equation is L C \frac{d^2 i}{d t^2} + \frac{L}{R} \frac{di}{dt}...
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