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Math Help - Evaluating this definite integral

  1. #1
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    Evaluating this definite integral

    It's the integral from 1 to 10 of x divided by x^2-4. I'm assuming u would be x^2-4 making du 2x so du/2 would be x. Then would I just be left with 1/2 the integral of 1/u and would have to solve it from there?
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  2. #2
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    Quote Originally Posted by fattydq View Post
    It's the integral from 1 to 10 of x divided by x^2-4. I'm assuming u would be x^2-4 making du 2x so du/2 would be x. Then would I just be left with 1/2 the integral of 1/u and would have to solve it from there?
    If your integral is

    \int_1^{10} \frac{x}{x^2-4}\,dx

    then you have a problem at -2 and 2! Your integral is improper!
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  3. #3
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    Quote Originally Posted by danny arrigo View Post
    If your integral is

    \int_1^{10} \frac{x}{x^2-4}\,dx

    then you have a problem at -2 and 2! Your integral is improper!
    What? What does this mean then? I understand it's that way because it'd turn out to be 0 but...it's an online homework assignment and there has to be some sort of response.
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  4. #4
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    It must be a typo on the problem or those aren't the right bounds.

    You're learning how to evaluate definite integrals, but you can't do this one because the function ain't continuous at x=2. Regarding those bounds, we have 1\le x\le10 and 2 belongs there.

    If the question does not include the -2 neither 2, then you can evaluate the integral.
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