Results 1 to 8 of 8

Math Help - indefinite integral

  1. #1
    Member
    Joined
    Feb 2010
    Posts
    98

    indefinite integral

    I have no idea why the homework is telling me I'm getting the wrong answer.. I'm following exactly how they did it in the book.. Let me know what you guys get

    Evaluate the indefinite integral:
    ___________
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,111
    Thanks
    2
    Did you get something like: \frac{1}{12}\cdot (2x+9)^{6} + C

    They didn't expand the silly binomial, did they?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Feb 2010
    Posts
    98
    Quote Originally Posted by TKHunny View Post
    Did you get something like: \frac{1}{12}\cdot (2x+9)^{6} + C

    They didn't expand the silly binomial, did they?
    nope i guess not I kept getting (1/30) instead of (1/12)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,111
    Thanks
    2
    Hmmm... Where does that leave us? Did the book get it right?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    Quote Originally Posted by tbenne3 View Post
    I have no idea why the homework is telling me I'm getting the wrong answer.. I'm following exactly how they did it in the book.. Let me know what you guys get

    Evaluate the indefinite integral:
    ___________
    let u = 2x+9 \implies du = 2 dx \implies dx=\frac{du}{2}

    substitute u , dx in your question and integrate. You should end up with the expression provided by TKHunny in post#2
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,454
    Thanks
    1868
    Quote Originally Posted by tbenne3 View Post
    I have no idea why the homework is telling me I'm getting the wrong answer.. I'm following exactly how they did it in the book.. Let me know what you guys get

    Evaluate the indefinite integral:
    ___________
    I don't see any way to tell what you are doing wrong if you don't show what you are doing!
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Newbie
    Joined
    Apr 2010
    Posts
    4
    Quote Originally Posted by tbenne3 View Post
    I have no idea why the homework is telling me I'm getting the wrong answer.. I'm following exactly how they did it in the book.. Let me know what you guys get

    Evaluate the indefinite integral:
    ___________
    1/12*(2*x+9)^6
    Follow Math Help Forum on Facebook and Google+

  8. #8
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    Quote Originally Posted by mahm32 View Post
    1/12*(2*x+9)^6
    Thats exactly what TKHunny has said in post number 2.

    Isn't your book following the substution method?

    let u = 2x+9 \implies du = 2 dx \implies dx=\frac{du}{2}

    now your integral becomes:

    \int (2x+9)^5 dx = \int u^5 \frac{du}{2} = \frac{1}{2} \int u^5 du

    now integrate, and substitute u=2x+9 after your integration is complete!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Indefinite integral
    Posted in the Calculus Forum
    Replies: 6
    Last Post: July 28th 2010, 10:30 AM
  2. indefinite integral
    Posted in the Calculus Forum
    Replies: 4
    Last Post: April 30th 2010, 03:10 AM
  3. indefinite integral
    Posted in the Calculus Forum
    Replies: 3
    Last Post: March 1st 2010, 11:16 AM
  4. Indefinite Integral
    Posted in the Calculus Forum
    Replies: 3
    Last Post: February 5th 2010, 08:05 AM
  5. Indefinite Integral
    Posted in the Calculus Forum
    Replies: 3
    Last Post: November 19th 2007, 11:56 AM

Search Tags


/mathhelpforum @mathhelpforum