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Math Help - Finding exponential growth rate

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    Finding exponential growth rate

    THe population of Murrayville doubled in 30 years. What was the exponential growth rate?
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    This question is exactly similar to the last question i answered for you.

    n = \frac{ln2}{ln(1 + r/100)}

    where n is the doubling period

    so n = 30

    and r is the rate
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by dc52789 View Post
    THe population of Murrayville doubled in 30 years. What was the exponential growth rate?
    r = \frac {\ln 2}t

    where r is the rate of growth and t is the doubling time

    (note that the same formula works for half-life)
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    Quote Originally Posted by treetheta View Post
    This question is exactly similar to the last question i answered for you.

    n = \frac{ln2}{ln(1 + r/100)}

    where n is the doubling period

    so n = 30

    and r is the rate
    where did you get 100?
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  5. #5
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    Quote Originally Posted by dc52789 View Post
    THe population of Murrayville doubled in 30 years. What was the exponential growth rate?
    An exponential function can always be written y= Ae^{kx}. The "exponential growth rate" is the constant, k.

    The population when x= 0 is Ae^0= A. 30 years later, x= 30 and the population is 2A: 2A= Ae^{30k} so [tex]e^{30k}= 2. Taking the logarithm of both sides 30k= ln(2) and k= ln(2)/30.
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  6. #6
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    Quote Originally Posted by dc52789 View Post
    where did you get 100?
    it's the formula q:

    refer to:
    Doubling time - Wikipedia, the free encyclopedia
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