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Homework Help: Fundemental theorem of Calc. question?

  1. Feb 1, 2010 #1
    1. The problem statement, all variables and given/known data
    Find function f(x) and constant a such that,

    6+ integral f(t)/t^2 dt = 2x
    limits are a to x

    2. Relevant equations
    I think I am on the right track could someone check this?

    3. The attempt at a solution
    if x = a then the integral will = 0,
    6 = 2a, a = 3 limits now are 3 to x,
    now,
    6 + integral f(x)/x^2 dx = 2x, fundamental theorem
    6 + f(x)/x^2 = 2 => 6 + f(x)= 2x^2 => f(x)= 2x^2 - 6
    Thanks!
     
  2. jcsd
  3. Feb 1, 2010 #2
    try to take the derivative of both sides and see what happens?
    on your last line, when you took the derivative, you missed something. what is the derivative of 6?
     
  4. Feb 1, 2010 #3
    Ok thanks that was the part I was not sure about so the derivative of 6 goes to 0.
    Thanks!
     
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