Results 1 to 9 of 9

Math Help - Finding the integral, can i get my answer checked?

  1. #1
    Member
    Joined
    Sep 2007
    From
    Colorado
    Posts
    145

    Finding the integral, can i get my answer checked?

    \int\frac{8}{(y-9)^3}dy
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Sep 2007
    From
    Colorado
    Posts
    145
    I get an answer of \frac{4}{(y-9)^2}+c is this correct?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,617
    Thanks
    1581
    Awards
    1
    It is the same as \int {8u^{ - 3} du} .
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Sep 2007
    From
    Colorado
    Posts
    145
    Quote Originally Posted by Plato View Post
    It is the same as \int {8u^{ - 3} du} .
    Yes if you let U=y-9.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Sep 2007
    From
    Colorado
    Posts
    145
    So is my answer right then?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,617
    Thanks
    1581
    Awards
    1
    Quote Originally Posted by Darkhrse99 View Post
    So is my answer right then?
    Yes. But I must ask why you don't know that it is correct?
    Did you differentiate your answer?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,623
    Thanks
    428
    Quote Originally Posted by Plato View Post
    Yes. But I must ask why you don't know that it is correct?
    Did you differentiate your answer?
    that's twice ...

    http://www.mathhelpforum.com/math-he...ed-please.html
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Member
    Joined
    Sep 2007
    From
    Colorado
    Posts
    145
    Quote Originally Posted by Plato View Post
    Yes. But I must ask why you don't know that it is correct?
    Did you differentiate your answer?
    The first time I did it, I was coming up with a negative 4, then I did it again and came with a positive 4. I was just making sure the negative answer I came up with was wrong!
    Follow Math Help Forum on Facebook and Google+

  9. #9
    MHF Contributor
    Joined
    Oct 2008
    Posts
    1,034
    Thanks
    49
    Just in case a picture helps ...



    (and helps with the checking by differentiating, too... check again!)

    As usual, straight continuous lines differentiate downwards with respect to y, and the straight dashed line with respect to the dashed balloon expression - so that the triangular network is the chain rule.

    Don't integrate - balloontegrate!

    http://www.ballooncalculus.org/forum.top.php
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: August 5th 2009, 11:32 AM
  2. Replies: 3
    Last Post: August 5th 2009, 11:14 AM
  3. Camn I get my answer checked out?
    Posted in the Calculus Forum
    Replies: 5
    Last Post: August 5th 2009, 10:20 AM
  4. I need this answer checked
    Posted in the Algebra Forum
    Replies: 5
    Last Post: July 27th 2008, 03:01 PM
  5. Need answer checked
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 9th 2008, 06:44 AM

Search Tags


/mathhelpforum @mathhelpforum