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Math Help - Evaluate a logarithmic function

  1. #1
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    Evaluate a logarithmic function

    Evaluate

    Please show work
    I got that the answer is 4 because 7log7 = 1
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  2. #2
    MHF Contributor ebaines's Avatar
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    Re: Evaluate a logarithmic function

    I would suggest that you start with the definition of the logarthm: If a^b = c then  \log_a c = b. Here 'a' is 7 and 'b' is \log_7 4, therefore from the right hand side of the definition \log_7 c = b = log_7 4. Hence c = 4, and 7^{\log_7 4} = 4.
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  3. #3
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    Re: Evaluate a logarithmic function

    You are absolutely right. You can also proceed like this. Let c = 7^(ln4 to the base 7) taking log on both sides we get (lnc to the base 7) = (ln4 to the base 7) and that gices c = 4. Hence 7^(ln4 to the base 7)= 4
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