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Homework Help: Graphing an Exponential

  1. Mar 21, 2006 #1
    11 A spoonful of sugar is dissolving in hot water. The initial mass of the sugar was 7 grams
    and 5 minutes later the mass present had halved. The mass of sugar, S grams, at time
    t minutes after it was placed in the hot water can be modelled by S(t) = S0e−kt, t ≥ 0.
    a State the value of S0.
    b Find the exact value of k.
    c Sketch the graph of S(t).
    d To the nearest second, how long after the sugar was
    placed in the hot water was its mass 1 gram?

    how do i graph part c on my calculator, which equation do i use to graph it?
     
  2. jcsd
  3. Mar 22, 2006 #2
    The problem doesn't ask you to use your calculator, it asks you to sketch the graph. Find the values of S0 and k, as per parts a and b. Then substitute those values into the given equation for S(t) and sketch from there.
     
  4. Mar 22, 2006 #3

    HallsofIvy

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    Science Advisor

    The problem asks you to graph S(t)= S0e-kt Why would you have to ask "which equation do I use to graph it"?
    Of course, you use the values of S0 and k you found in parts a and b.

    Or are you asking how to enter it into the calculatorf?
     
    Last edited by a moderator: Mar 23, 2006
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