Results 1 to 4 of 4
Like Tree4Thanks
  • 3 Post By romsek
  • 1 Post By hollywood

Math Help - Differential Equation help?

  1. #1
    Member
    Joined
    Feb 2014
    From
    USA
    Posts
    231

    Differential Equation help?

    I have this question: Differential Equation help?-capture3.jpgI actually got -2.9 though, not -3.2. :/ To get this I found that separated dy/dx=xcosx^2 is y=c+((sin(x^2)/2) So when I put (0,-3) into that I get that c=-3. So then when I plug pi in for x I get that (sin(9.8)/2)-3= -2.9 ..What am I doing wrong here? :/ Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Nov 2013
    From
    California
    Posts
    2,578
    Thanks
    1014

    Re: Differential Equation help?

    I don't know what you're doing wrong. Your reasoning is correct. (a) is the correct answer.

    I get that $\dfrac{\sin(9.8)}{2}-3=-3.18324$ which isn't the correct answer but it's not far off.

    Truncating $\pi^2$ to 9.8 so early isn't the best thing you could do.
    Thanks from canyouhelp, hollywood and topsquark
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Mar 2010
    Posts
    993
    Thanks
    244

    Re: Differential Equation help?

    I get \frac{\sin{\pi^2}}{2}-3 = -3.215.

    - Hollywood
    Last edited by hollywood; April 11th 2014 at 06:43 AM. Reason: factor of 1/2
    Thanks from canyouhelp
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Feb 2014
    From
    USA
    Posts
    231

    Re: Differential Equation help?

    Thank you both!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: May 8th 2011, 12:27 PM
  2. Replies: 1
    Last Post: April 11th 2011, 01:17 AM
  3. [SOLVED] Solve Differential equation for the original equation
    Posted in the Differential Equations Forum
    Replies: 5
    Last Post: February 21st 2011, 01:24 PM
  4. Partial differential equation-wave equation - dimensional analysis
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: August 28th 2009, 11:39 AM
  5. Replies: 13
    Last Post: May 19th 2008, 08:56 AM

Search Tags


/mathhelpforum @mathhelpforum