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Homework Help: Electrical circuit

  1. Oct 27, 2005 #1
    The problem is:
    "In an electrical circuit, the voltage, V volts, as a function of time, t minutes, is given by V = 12 - 9t + 2t^2. Determine the greatest and least values of voltage during the first 5 min. When do these values occur?"

    The answers given are exact.
    Least: 1.875 V @ 2.25 min
    Most: 17 V @ 5 min

    Well I know how to get the max, but the min?

    Thanks!!
     
  2. jcsd
  3. Oct 27, 2005 #2
    The graph is a parabola. You can find the vertex if you remember how, or you can find where the derivative is 0.
     
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