Results 1 to 3 of 3

Math Help - First-order differential equation problem

  1. #1
    Newbie
    Joined
    Apr 2012
    From
    UK
    Posts
    7

    First-order differential equation problem

    dy/dx=4(y^4) What I did: dx/dy = 1/(4(y^4); x= the integralof 0.25(y^-4) = -1/12(y^-3) + c The answer is at the back of the book is 3(y^3)(4x+c) + 1 =0..There's a whole dozen of other differential equations I can't do so I must be making some very fundamental mistake. Any help would be very appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Sep 2010
    Posts
    185
    Thanks
    13

    Re: First-order differential equation problem

    \begin{align*}\frac{dy}{dx}&=4y^4\\ \frac{dy}{y^4}&=4dx\\ \int y^{-4}dy&=4\int dx\\ \frac{y^{-3}}{-3}&=4x+c \bigg\slash \cdot 3y^3  \\ -1&=3y^3(4x+c)\\ 3y^3(4x+c)+1&=0\end{align*}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2012
    From
    UK
    Posts
    7

    Re: First-order differential equation problem

    Thank you so much for the quick and clear response!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. 2nd order differential equation problem
    Posted in the Differential Equations Forum
    Replies: 4
    Last Post: August 27th 2011, 12:56 PM
  2. Problem Solving First Order Differential Equation
    Posted in the Differential Equations Forum
    Replies: 5
    Last Post: March 17th 2011, 06:49 AM
  3. Second Order differential equation problem
    Posted in the Differential Equations Forum
    Replies: 1
    Last Post: March 8th 2010, 12:21 AM
  4. Problem with first order separabel differential equation
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: December 9th 2009, 05:29 PM
  5. First order differential equation problem
    Posted in the Differential Equations Forum
    Replies: 1
    Last Post: March 2nd 2009, 12:49 PM

Search Tags


/mathhelpforum @mathhelpforum