Results 1 to 4 of 4

Math Help - Integral

  1. #1
    Junior Member
    Joined
    Jan 2010
    Posts
    47

    Integral

    <br />
\int_{-\infty}^{\infty} \frac{dx}{x^2(1+e^x)}<br /> <br />

    <br />
\int_{1}^{\infty} \frac{e^-x}{\sqrt{x}}dt<br />

    i can't find the anti-derivative of these
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,111
    Thanks
    2
    1) Assuming they converge, the definite integral has a specific value. Call the value "A". The subsequent anti-derivative, then, would be Ax + C.

    2) Can you prove that they converge? I'm worried about that first one around x = 0.

    3) That last one is kind of an Error Function, isn't it? Maybe its complement?

    4) What is your assignment and why do you believe either anti-derivative can be determined?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jan 2010
    Posts
    47
    Quote Originally Posted by TKHunny View Post
    1) Assuming they converge, the definite integral has a specific value. Call the value "A". The subsequent anti-derivative, then, would be Ax + C.

    2) Can you prove that they converge? I'm worried about that first one around x = 0.

    3) That last one is kind of an Error Function, isn't it? Maybe its complement?

    4) What is your assignment and why do you believe either anti-derivative can be determined?
    I have to find out if they converge or diverge.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Nov 2009
    Posts
    202
    Quote Originally Posted by larryboi7 View Post
    I have to find out if they converge or diverge.
    the first one is divergent.

    the second one seems to be reducible to some form of the gamma function.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: August 31st 2010, 07:38 AM
  2. Replies: 1
    Last Post: June 2nd 2010, 02:25 AM
  3. Replies: 0
    Last Post: May 9th 2010, 01:52 PM
  4. [SOLVED] Line integral, Cauchy's integral formula
    Posted in the Differential Geometry Forum
    Replies: 3
    Last Post: September 15th 2009, 01:28 PM
  5. Replies: 0
    Last Post: September 10th 2008, 07:53 PM

Search Tags


/mathhelpforum @mathhelpforum