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Homework Help: Max and min problem with 3 unknowns

  1. Jan 20, 2010 #1

    I have this question for a college assignment. It involves 3 'unknowns' (not 3 variables, since 2 are constants). The main difficulty I am having is inexperience with max and min problems where you cannot fully evalaute the solution.

    I think I have made a reasonable attempt at a solution, I would appreciate it if someone would take a brief look tell me what you think.


    1. The problem statement, all variables and given/known data

    Find V for maximum E, hence find E_max.

    u and [tex]\theta[/tex] are constants.

    2. Relevant equations

    Product rule: [tex]\frac{dy}{dx}=u\frac{dv}{dx}+v\frac{du}{dx}[/tex]

    3. The attempt at a solution
    Last edited: Jan 21, 2010
  2. jcsd
  3. Jan 20, 2010 #2


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    Staff: Mentor

    Looks fine to me (although I just skimmed some of the algebra). Do you know yet if it's the correct answer?
  4. Jan 20, 2010 #3

    Hi, thanks for taking a look at my question.

    The whole assignment isn't due for a week or so yet, so I won't find out for a while.

    I am somewhat confident of my approach but was just wanting someone to look it over.

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