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Find Exponential Equation from data points

  1. Aug 25, 2012 #1
    Hi guys I'm helping my girlfriend with her Calc 1 homework and we seem to be stuck on this one problem. Am I missing something obvious?

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

    2. Relevant equations

    [itex]
    P = P_0 a^t
    [/itex]

    [itex]
    \frac{5}{20} = \frac{P_0 a^1}{P_0 a^{-1}}
    [/itex]

    [itex]
    \frac{1}{4} = a^2
    [/itex]

    [itex]
    a = \frac{1}{2}
    [/itex]

    [itex]
    5 = P_0 (1/2)^1
    [/itex]

    [itex]
    P_0 = 10
    [/itex]

    [itex]
    P(t) = 10 (1/2)^t
    [/itex]
     
  2. jcsd
  3. Aug 25, 2012 #2
    ... and a few seconds after I posted this, I realized that we're using the wrong variable. X instead of t, and it works.

    Rage! Rage factorial smiley-bangheadonwall.gif
     
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