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Math Help - proving integral is negative (help!)

  1. #1
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    proving integral is negative (help!)




    I did the first part already, by letting
    u = ax => dx = du/a, then just substituting in the values.
    How do i explain why its negative?
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  2. #2
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    Quote Originally Posted by gomes View Post



    I did the first part already, by letting
    u = ax => dx = du/a, then just substituting in the values.
    How do i explain why its negative?
    For x > 0, e^x>1+x. Take reciprocals to get e^{-x}<(1+x)^{-1}. So the integrand is always negative and hence so is the integral.
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  3. #3
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    Quote Originally Posted by Opalg View Post
    For x > 0, e^x>1+x. Take reciprocals to get e^{-x}<(1+x)^{-1}. So the integrand is always negative and hence so is the integral.
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