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Homework Help: Modelling with polynomials

  1. Aug 6, 2006 #1
    5 A particle moves horizontally in a straight line according to the rule
    x(t) = t^3 − 5t^2 + 3t − 5, 0 ≤ t ≤ 7
    where x metres is its displacement to the right of the origin at time t seconds.
    a What is the initial position of the particle?
    b After how many seconds does the particle pass through the origin, correct to 2 decimal

    i need help on part b. could some one help me please?
    thank you
  2. jcsd
  3. Aug 6, 2006 #2


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    Gold Member

    When it passes the origin, the displacement is 0 right? Therefore, you could say that x(t)=0 when it passes the origin. So just find the root of the equation that suits the given domain.
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