Results 1 to 3 of 3

Math Help - different int. by parts

  1. #1
    Member
    Joined
    Jan 2009
    Posts
    100

    different int. by parts

    \int \frac{2x}{e^x}dx

    I tried:
    u=2x
    dv= e^{-x}dx

    but I got a funky answer. Is this the correct substitution?

    Still learning which to use when...lol
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Behold, the power of SARDINES!
    TheEmptySet's Avatar
    Joined
    Feb 2008
    From
    Yuma, AZ, USA
    Posts
    3,764
    Thanks
    78
    Quote Originally Posted by saiyanmx89 View Post
    \int \frac{2x}{e^x}dx

    I tried:
    u=2x
    dv= e^{-x}dx

    but I got a funky answer. Is this the correct substitution?

    Still learning which to use when...lol

    Yes.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Dec 2008
    From
    Scotland
    Posts
    901
    Quote Originally Posted by saiyanmx89 View Post
    \int \frac{2x}{e^x}dx

    I tried:
    u=2x
    dv= e^{-x}dx

    but I got a funky answer. Is this the correct substitution?

    Still learning which to use when...lol
     \int \frac{2x}{e^x}dx = \int 2xe^{-x}dx

     = 2 \bigg(\bigg[ -xe^{-x}\bigg] - \int -e^{-x} dx \bigg)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. int by parts
    Posted in the Calculus Forum
    Replies: 4
    Last Post: April 19th 2010, 06:21 PM
  2. Do I have to use By Parts?
    Posted in the Calculus Forum
    Replies: 2
    Last Post: March 4th 2010, 06:59 AM
  3. Int. by parts (x-1)e^2x-1
    Posted in the Calculus Forum
    Replies: 2
    Last Post: December 15th 2009, 03:57 AM
  4. Another Inegration by Parts
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 21st 2009, 08:01 AM
  5. PARTS HELP IM NEW HERE
    Posted in the Calculus Forum
    Replies: 13
    Last Post: September 26th 2008, 09:39 AM

Search Tags


/mathhelpforum @mathhelpforum