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Finding roots in an equation

  1. Nov 23, 2008 #1
    1. The problem statement, all variables and given/known data

    show that the equation x^4+x^3-4x^2-1=0

    2. Relevant equations

    3. The attempt at a solution
    I wasn't sure where to start. The minus one at the end really threw me off. I tried to factor by grouping by coul;dn't figure out what to do with the -1
  2. jcsd
  3. Nov 23, 2008 #2
    Have you learned the rational root test?
  4. Nov 23, 2008 #3
    This equation has no "nice" roots. You might want to use a numerical approximation or have a look into "http://en.wikipedia.org/wiki/Quartic_equation#Solving_a_quartic_equation" [Broken].:smile:
    Last edited by a moderator: Apr 23, 2017 at 10:17 PM
  5. Nov 23, 2008 #4


    Staff: Mentor

    What's the rest of the sentence?
    Show that this equation does what?

    Please give us the exact wording of the problem.
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