Results 1 to 3 of 3

Math Help - Find maximum and draw the graph of S(x)=I|xcosx|dx from 0->3pi/2

  1. #1
    Newbie
    Joined
    Nov 2010
    Posts
    4

    Find maximum and draw the graph of S(x)=I|xcosx|dx from 0->3pi/2

    Hi!

    I am stuck with this excersice, which needs to be done by tomorrow.
    Find maximum and draw the graph of S(x)=I|xcosx|dx from 0->s in the intervall [0,3pi/2]
    I is integral....

    Can someone help me get started?

    Thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor FernandoRevilla's Avatar
    Joined
    Nov 2010
    From
    Madrid, Spain
    Posts
    2,162
    Thanks
    44
    Quote Originally Posted by StefanO View Post
    Find maximum and draw the graph of S(x)=I|xcosx|dx from 0->s in the intervall [0,3pi/2] I is integral....
    The problem is ill defined. For example:

    S(2)=\displaystyle\int|2\cos 2| d2 ( what does this means? )

    Possibly the function is:

    S(x)=\displaystyle\int_0^x|t\cos t| dt.

    Then:

    S'(x)=|x\cos x|.

    Regards.

    Fernando Revilla
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Nov 2010
    From
    Staten Island, NY
    Posts
    451
    Thanks
    2
    I believe that the function should be written S(s) (as opposed to S(x) ).

    You need to first find the critical numbers in the given interval. To do this set the derivative of S equal to 0.

    To compute the derivative of S you need to apply the second fundamental theorem of calculus which essentially says that "a derivative cancels out an integral." (Don't take this too literally though).

    So S'(s)=s\cos s.

    I hope this gets you started.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Find maximum point of curve graph
    Posted in the Pre-Calculus Forum
    Replies: 7
    Last Post: September 29th 2011, 09:49 AM
  2. How to draw a graph
    Posted in the LaTeX Help Forum
    Replies: 6
    Last Post: June 23rd 2010, 05:52 PM
  3. How to find the maximum point of a graph
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: May 2nd 2010, 03:49 PM
  4. Replies: 2
    Last Post: August 26th 2009, 04:51 AM
  5. Replies: 1
    Last Post: March 1st 2009, 10:58 AM

Search Tags


/mathhelpforum @mathhelpforum