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Math Help - half life

  1. #1
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    Post half life

    I have the function A(t) with its differential equation of dA/dt= -kA
    and the solution as a function: A(t)= Ao e^-kt.

    I need to find the values of Ao and k in the equation A(t) before i
    can continue with the rest of the question.

    I think i've found the values for k but not 100% but have no idea
    about Ao

    i found k= 1.2092x 10^-4
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by bungy189 View Post
    I have the function A(t) with its differential equation of dA/dt= -kA
    and the solution as a function: A(t)= Ao e^-kt.

    I need to find the values of Ao and k in the equation A(t) before i
    can continue with the rest of the question.

    I think i've found the values for k but not 100% but have no idea
    about Ao

    i found k= 1.2092x 10^-4
    We can't help you until you tell us what your boundary conditions are.

    -Dan
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  3. #3
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    The question is to do with the amount of C-14 as a percentage. The half life of C14 is 5730....
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  4. #4
    Forum Admin topsquark's Avatar
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    Your k value is correct (well, I get k = ln(2)/5730 \approx 1.2097 \times 10^{-4}.)

    The physical meaning of A_0 is the amount of C-14 present at time 0. You can't determine that from the information you have given us.

    -Dan
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