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Find derivative using FTC1

  1. Nov 25, 2008 #1
    I need to find the derivative of the function below...

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

    [itex]G(x) = \int_{x}^{1} cos(\sqrt{t}) dt[/itex]

    2. Relevant equations


    If f is continuous on [a,b], then the function g defined by

    [itex]g(x) = \int_{a}^{x} f(t) dt[/itex] [itex]a \leq x \leq b[/itex]

    is continuous on [a,b] and differentiable on (a,b) and [itex]g'(x) = f(x)[/itex]

    3. The attempt at a solution

    Would it be [itex]-cos(sqrt(t))[/itex]

    Thanks for the time!
    Last edited: Nov 25, 2008
  2. jcsd
  3. Nov 25, 2008 #2


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    Science Advisor

    It would be [itex]-cos(\sqrt{x})[/itex], not t.
  4. Nov 25, 2008 #3


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    Homework Helper

    First you might reverse the limits, which reveses the sighn. FTC1 says the derivative of the integral of a function is the function. Differendiation cancels integration.
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