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Homework Help: HW help

  1. Feb 14, 2008 #1
    HW help!!!

    1. The problem statement, all variables and given/known data

    consider the differential equation dy/dx = (y-1)^2 cos(Πx)

    a.There is a horizontal line with y =c that satisfies this equation. Find the value of c
    b. Find the particular solution y =f(x) tot the differential equation with the initial condition f(1) = 0

    2. Relevant equations

    n/a

    3. The attempt at a solution

    I tried to do the problem, but I cant separate the y variables from the x, help!
     
  2. jcsd
  3. Feb 14, 2008 #2
    (a) What happens when you plug y=c to the differential equation? You should get just an equation depending on c (and x, but if you restrict x, you can divide it out).
    (b) Try multiplying each side by dx/(y-1)^2 and integrating directly. Then, you can either use your initial conditions as your integration limits or plug them in to find your integration constant.
     
  4. Feb 14, 2008 #3
    I got it, I got c=1 thanks
     
  5. Feb 15, 2008 #4

    HallsofIvy

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    Science Advisor

    While it is, in fact, almost trivial to separate x and y ((y-1)2 and cos([itex]\pi[/itex]), in effect, are separated- they are multiplied), you don't have to find the general solution to answer (b)!
     
  6. Feb 16, 2008 #5
    i dont know much but i do know that u need to get your basics right. come see the lastest post in my blog. the web link may be of help
     
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