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-   -   Exponential and logarithmic equations (https://www.askmehelpdesk.com/showthread.php?t=207754)

  • Apr 20, 2008, 10:07 AM
    jordan716
    exponential and logarithmic equations
    I am having difficulty with setting two exponential growth equations equal to one another to find where they catch up (intersect) with each other. I have this so far:

    (1.03) ^ t/5 = .4 (1.08) ^ t/3 .

    My professor gave me a hint of ln(ab) = ln(a) + ln(b), but I'm not sure where to go with that.

    Any help would be greatly appreciated!
  • Apr 20, 2008, 11:37 AM
    ISneezeFunny
    when you put "ln" onto a number, the exponent "comes down in front"

    (t/5)*ln (1.03) = ln (.4*(1.08^(t/3)))

    then, using the professor's hint

    (t/5)*ln (1.03) = ln (0.4) + (t/3)*ln(1.08)

    and take it from there.
  • Apr 20, 2008, 10:17 PM
    jordan716
    Thank you so much! That helped a lot. :)

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