Results 1 to 5 of 5

Math Help - Quick Question - Integration

  1. #1
    Newbie
    Joined
    Jun 2008
    Posts
    2

    Quick Question - Integration

    While doing some exercises in my cal II book i stumbled on these 2 questions.. Any help will be appreciated. Thanks

    (1) The integral of tan3x --> -1/3ln|cos3x|?
    (2) The integral of x/(x^(2)-1)^2 --> not sure
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Lord of certain Rings
    Isomorphism's Avatar
    Joined
    Dec 2007
    From
    IISc, Bangalore
    Posts
    1,465
    Thanks
    6
    Quote Originally Posted by Bure03 View Post
    While doing some exercises in my cal II book i stumbled on these 2 questions.. Any help will be appreciated. Thanks

    (1) The integral of tan3x --> -1/3ln|cos3x|?
    (2) The integral of x/(x^(2)-1)^2 --> not sure
    (1) Substitute u = \cos 3x

    (2) Substitute u = x^2 - 1
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Rhymes with Orange Chris L T521's Avatar
    Joined
    May 2008
    From
    Santa Cruz, CA
    Posts
    2,844
    Thanks
    3
    Quote Originally Posted by Bure03 View Post
    While doing some exercises in my cal II book i stumbled on these 2 questions.. Any help will be appreciated. Thanks

    (1) The integral of tan3x --> -1/3ln|cos3x|?
    (2) The integral of x/(x^(2)-1)^2 --> not sure
    #1 \int\tan(3x)\,dx=\int\frac{\sin(3x)}{\cos(3x)}\,dx

    Make the substitution z=\cos(3x)

    #2 \int\frac{x\,dx}{(x^2-1)^2}

    Make the substitution z=x^2-1

    Try taking it from here.

    Hope this makes sense!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Rhymes with Orange Chris L T521's Avatar
    Joined
    May 2008
    From
    Santa Cruz, CA
    Posts
    2,844
    Thanks
    3
    Quote Originally Posted by Bure03 View Post
    While doing some exercises in my cal II book i stumbled on these 2 questions.. Any help will be appreciated. Thanks

    (1) The integral of tan3x --> -1/3ln|cos3x|?
    Yes, that's correct. It can also be written as \frac{1}{3}\ln|\sec(3x)|.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jun 2008
    Posts
    2
    thanks guys just wanted to double check my answers.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Integration question ( really quick)
    Posted in the Calculus Forum
    Replies: 3
    Last Post: November 30th 2010, 10:53 PM
  2. integration :quick question
    Posted in the Calculus Forum
    Replies: 9
    Last Post: February 19th 2010, 08:24 AM
  3. Quick integration question
    Posted in the Calculus Forum
    Replies: 4
    Last Post: September 14th 2009, 12:44 PM
  4. quick integration question
    Posted in the Calculus Forum
    Replies: 4
    Last Post: March 9th 2009, 05:24 PM
  5. quick integration question...
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 26th 2008, 04:18 PM

Search Tags


/mathhelpforum @mathhelpforum