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Homework Help: Need help with an antiderivitive

  1. Feb 6, 2009 #1
    I can't seem to get this antiderivitive correct: sqrt(20-x) from 0 to 20.

    I end up with -(2/3)(sqrt(20-x)^(3/2) which is zero evaluated at either of the two limits.

    This is not correct since the area below the curve of the original equation is definately not 0.
  2. jcsd
  3. Feb 6, 2009 #2


    Staff: Mentor

    You shouldn't have sqrt in your answer since that's already accounted for in the 3/2 exponent. Also, the antiderivative functionis not zero for x = 0. Check it again.
  4. Feb 7, 2009 #3


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    Homework Helper
    Gold Member

    Yes and also it is not zero at both the limits; it should work out now.
  5. Feb 7, 2009 #4
    oops, i meant to write -(2/3)(20-x)^(3/2), but yeah, i didn't evaluate it correctly the first time. It should be:


    *Facepalm* I blame it on lack of sleep, haha.

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