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Math Help - find the integral(2)

  1. #1
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    find the integral(2)

    1. \int\frac{sinx}{x}dx
    2. \int_{-00}^{00} (cosx)e^{-x^{2}/2}dx
    Last edited by chialin4; March 9th 2010 at 06:10 AM.
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  2. #2
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    Quote Originally Posted by chialin4 View Post
    \int\frac{sinx}{x}dx
    \int \frac{\sin(x)}{x}dx=\text{SinIntegral(x)}

    . . . stop special function discrimination: equal rights for special functions.
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  3. #3
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    Quote Originally Posted by shawsend View Post
    \int \frac{\sin(x)}{x}dx=\text{SinIntegral(x)}

    . . . stop special function discrimination: equal rights for special functions.
    ???
    what do u mean ?
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  4. #4
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    Quote Originally Posted by chialin4 View Post
    ???
    what do u mean ?
    You can not solve this integrals in terms of elementary function.
    This well-known integral is used in electrical engineering.
    See:
    integrate sin(x)/x - Wolfram|Alpha
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  5. #5
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    Quote Originally Posted by chialin4 View Post
    ???
    what do u mean ?
    Hi. It's a suggestion to treat "special functions" like antiderivatives of integrals that can't be expressed in simple terms, in the same way that you treat \sin(x) so if I have \int \cos(x)dx you say "hey, that's easy, it's \sin(x). So hey, \int \frac{sin x}{x} is easy. It's . . .

    Also, for that second we did that one here:

    http://www.mathhelpforum.com/math-he...x-e-x-2-a.html
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