Recent content by Larry Cosner

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    Would Staring at Laptop in Dim Lit Room be Bad?

    You can assure your folks, from a medical perspective, that there is no innately harmful potential to using a laptop in a dimly lit room. The gradient between screen lighting and ambient (room) lighting may impact how quickly your eyes tire. But there is no long-term biophysical harm that...
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    The (asserted) equivalence of first partial derivatives

    In the solution to a differential-equation problem -- proof of the existence of an integrating factor -- the following statements are made regarding a general function "u(xy)" [that is, a function of two variable that depends exclusively on the single factor "x*y"]...
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    Encountering "unsolvable equation" during simple ODE problem

    Funny you should mention this. Found out a couple of days ago that I was eligible (through an association between my hospital and the local Community College) to purchase Version 10. So, a few minutes, a bit of typing, some electrons running about the Internet (sort of), and me and my credit...
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    Encountering "unsolvable equation" during simple ODE problem

    Thank you to all who replied; I had begun to suspect -- but lacked the mathematic knowledge/terminology to articulate -- that the equation was, by definition, and unsolvable. So explaining the fact, and why, was VERY helpful! (I sort of wish that the text-book authors would have indicated --...
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    As Requested New (though old) Member Introduction

    OK, so first we have to check your HMO status ... :)) (But seriously; I'm actually fine w/ discussing clinical stuff, as long as everybody involved recognizes that here I can't be considered a "really doctor" (in the words of one of my [now grown] daughters, circa kindergarden). Still, it is...
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    As Requested New (though old) Member Introduction

    I'm a near-60 physician w/ some research interests at the periphery of my career (mostly a clinician). Since I enjoy looking at things through a mathematical lens, I occasionally stumble onto research possibilities that pique my interest. I've one such now, but it will take a little more...
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    Encountering "unsolvable equation" during simple ODE problem

    Homework Statement {Prob #27, Section 2.1 "EDE" (Boyce/Prima, 10thEd), pp. 40} "Consider the initial value problem [and] find the coordinates for the first local maximum point of the solution, t>0." Homework Equations y' + (1/2)y = 2cost y(0) = -1 The Attempt at a Solution I...