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Homework Help: Derivative of the function

  1. May 8, 2008 #1
    1. The problem statement, all variables and given/known data

    the antiderivative for 5[tex]\sqrt{}x[/tex]

    2. Relevant equations



    3. The attempt at a solution

    It almost looks like the derivative of the function [tex]\sqrt{}x[/tex]
     
  2. jcsd
  3. May 8, 2008 #2
    [tex]\int 5\sqrt{x} = \int 5x^{1/2}[/tex]

    So just use the power rule for integrals.
     
  4. May 8, 2008 #3
    revised

    the actual problem is:
    Evaluate the definite integral [tex]\int^{7}_{1}[/tex] 5/[tex]\sqrt{}x[/tex]
    using the power rule I got:
    5[(x^3/2)/(3/2)] evaluating them at the end points 1 and 7, the answer I get after using FTC II is:-58.400 and is incorrect.
    What am I doing wrong? please help
     
  5. May 8, 2008 #4

    Defennder

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    Homework Helper

    Do you mean [tex]\int_1^7 \frac{5}{\sqrt{x}} \ dx[/tex]?

    If so, then x^(3/2) shouldn't be part of your answer.
     
  6. May 9, 2008 #5
    Yes (to part one)
    then how should I find the antiderivative? for 5/[tex]\sqrt{}x[/tex]
     
  7. May 9, 2008 #6

    Defennder

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    You must first find the antiderivate for [tex]x^{-\frac{1}{2}}[/tex]. Use the power rule for integrals as Feldoh said.
     
  8. May 9, 2008 #7
    Thanks for your help!!!!
     
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