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Homework Help: Newtons Method problem

  1. Mar 30, 2012 #1
    1. The problem statement, all variables and given/known data
    I've attached the question

    2. Relevant equations
    x(n+1) = x(n) - f(x(n)) / f '(x(n))

    3. The attempt at a solution
    2.5x^3 =2cos(x) + 8
    okay so this has to be in the form of f(x) = .... but there is no y variable for me to make it into that form. once i've gotten it into that form, it should be easy but its the manipulation thats got me stuck.
    0 =2cos(x) + 8 - 2.5x^3

    Attached Files:

  2. jcsd
  3. Mar 30, 2012 #2
    You want it in the form of f(x) = 0, and you have the equation 0 = 2cos(x) + 8 - 2.5x^3, so f(x) = 2cos(x) + 8 - 2.5x^3
  4. Mar 30, 2012 #3
    oh i didnt know that, i got an answer of x1=1.508306, x2=1.48451 and x3=1.48416 looks right
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