Recent content by daoshay

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    What is the residue of a branch cut?

    I've got \frac{1}{e^\frac{i\pi}{8}2i} as one residue and \frac{1}{e^\frac{3i\pi}{8}(-2i)} As the other. Any encouragement to continue or abandon ship? I'll be going to my professors last office hours with this stuff, so I'll find out one way or another. Thanks...
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    What is the residue of a branch cut?

    Homework Statement I'm finding the residues of the branch cut of \int^\infty_0 \frac{dx}{x^{1/4}(x^2+1)}dx Homework Equations The Attempt at a Solution I am trying to find the residue of i I am not sure how to handle lim z->i of \frac{1}{z^\frac{1}{4}(z+i)} Any nudges...
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    Residues of an essential singularity and a simple pole

    Thanks, Halls. I realized as soon as Vela pointed that out that I shouldn't have reciprocated because of the factorials. Only the z value is reciprocated. I'd been staring at this stuff for a while and wasn't thinking clearly. You guys have been a great help.
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    Residues of an essential singularity and a simple pole

    Thanks count. Will I end up getting -f(1), f(1/1)? I haven't tried it, but based on this problem and the behavior of the essential singularity times the analytic function, that's what I'm guessing I'll get. I -will- try it later this week.
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    Residues of an essential singularity and a simple pole

    So, I've got -sin(1) and sin(1) as the residues? That feels awkward, only because none of the examples we did had residues like that. But I suppose those are numbers too.
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    Residues of an essential singularity and a simple pole

    So, I've got: \frac {1}{z}\left(1-\frac{1}{3!}+\frac{1}{5!}-\frac{1}{7!}+\cdots\right) where the alternating series is my residue and that has a limit of... (I don't recognize this one except for the coefficients in sin(x))
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    Residues of an essential singularity and a simple pole

    Thanks, Vela. For now, I'm okay with the residue of 1 being -sin(1). I'm really uncertain about how to handle the 0 singularity. Do you suggest I expand the function into the Laurent series and find the -1 coefficient? If so, do I need to substitute \frac{e^{i1/z}-e^{-i1/z}}{2i}...
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    Residues of an essential singularity and a simple pole

    Homework Statement Classify the isolated singularities and find the residues \frac {\sin(\frac {1}{z})}{1-z} Homework Equations I know the Taylor series expansion for 1/(1-z) when |z|<1 and I think I know the Taylor series for sin(1/z). The reciprocal of each term of the Taylor series of...
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    Hard Laurent series. A little lost.

    Now that I've got the infinite sum, should I write it out as the difference of two summations? Or is it typically acceptable to write it out as the sum of terms with a clear pattern? I will go and ask my professor about his preferred notation anyhow.
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    Hard Laurent series. A little lost.

    I think I've got it. Sum from n=3 -> infinity of 2^n/z^(n+4) - Sum from n=3 -> infinity of 2^(3n+2)/z^(3n+6) because when I multiply and combine terms I get 2^3/z^7+2^4/z^8+2^6/z^10+2^7/z^11+... I'm sorry about my format, latex is too smart for me.
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    Hard Laurent series. A little lost.

    When you say multiply out and collect terms, do you mean I need to write it out as: 8(z+2)/z^8 + 8^2(z+2)/z^11 + ... (tried to type it in latex, but it calculated it back to f(z)... impressive!) and that is the Laurent series?
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    Hard Laurent series. A little lost.

    Homework Statement find the Laurent series for \frac{z+2}{z^{5}-8z^{2}} in 2<|z|<\infty Homework Equations The Attempt at a Solution Well, I factored out z^{5} in the denominator, which left me with a geometric sum (since |z|>2). I've come up with...
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    Unbiased estimator/MSE from a Gamma dist.

    I'm sorry, I was rushed while typing that up and I'm afraid I wasn't clear. I found the MLE for the parameter theta. I am supposed to test it for all theta for bias and then find the MSE of theta-hat. Based on the gamma family, the mean of this distribution should be 4theta --> theta =...
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    Unbiased estimator/MSE from a Gamma dist.

    I have given some serious effort to working out and understanding the MLE of a distribution. From the distribution f(x;\theta)= x^{3}e^{-x/\theta}/(6\theta^{4}), I have gotten the MLE theta-hat = xbar/4 I have a lot of difficulty figuring out if it is an unbiased estimator or not. How do I...
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