Results 1 to 3 of 3

Thread: Trig Integral

  1. January 1st 2011, 09:54 AM #1
    Spoolx
    Spoolx is offline
    Newbie
    Joined
    Dec 2010
    Posts
    17

    Trig Integral

    Having trouble with this problem
    \int COS^2{3x}

    So I used my power reducing formula to get here

    \int \frac{1+cos6X}{2}

    I pull a .5 out front
    \frac12 \int cos6x

    U Sub
    u=6x \ du=6dx

    Put a 1/6 out front
    \frac{1}{12} \int cosUdu \\ = \\ \frac{1}{12}sinx + c

    My book has a different answer, but I think I am right?
    Follow Math Help Forum on Facebook and Google+
  2. January 1st 2011, 09:56 AM #2
    Liverpool
    Liverpool is offline
    Member
    Joined
    Sep 2010
    Posts
    98
    \dfrac{1+cos(6x)}{2}=\dfrac{1}{2}(1+cos(6x)) \neq \dfrac{1}{2}(cos(6x))
    Follow Math Help Forum on Facebook and Google+
  3. January 1st 2011, 10:00 AM #3
    Spoolx
    Spoolx is offline
    Newbie
    Joined
    Dec 2010
    Posts
    17
    Ahh yes, thanks for correcting my mistake!
    Follow Math Help Forum on Facebook and Google+
« Stuck on an Integration | Integrate LN2x/x^2 »

Similar Math Help Forum Discussions

  1. A Trig Integral
    Posted in the Calculus Forum
    Replies: 5
    Last Post: January 17th 2011, 03:08 PM
  2. Trig Integral
    Posted in the Calculus Forum
    Replies: 7
    Last Post: January 1st 2011, 01:06 PM
  3. Help with a trig integral
    Posted in the Calculus Forum
    Replies: 2
    Last Post: March 2nd 2010, 12:43 PM
  4. trig integral
    Posted in the Calculus Forum
    Replies: 2
    Last Post: April 25th 2009, 04:35 AM
  5. trig integral
    Posted in the Calculus Forum
    Replies: 2
    Last Post: March 18th 2009, 08:51 PM

/mathhelpforum @mathhelpforum