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Math Help - logarithms help

  1. #1
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    logarithms help

    hi, im powering through an advanced functions course right now by myself at home and could use some help.

    1. Given that log 2 5 aproximately equals 2.3219
    find an aproximation for log 2 20

    2. 2log m + 3log m = 10 where there is no base on the logarithm.


    thanks in advanced(crappy pun intended)
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  2. #2
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    Quote Originally Posted by way123 View Post
    hi, im powering through an advanced functions course right now by myself at home and could use some help.

    1. Given that log 2 5 aproximately equals 2.3219
    find an aproximation for log 2 20

    2. 2log m + 3log m = 10 where there is no base on the logarithm.


    thanks in advanced(crappy pun intended)
    1. \log_2(20) = \log_2(4 \cdot 5) = \log_2(4) + \log_2(5)

    2. no base is usually base 10 for beginners ...

    2\log{m} + 3\log{m} = 5\log{m} = 10

    \log{m} = 2

    change to an exponential equation to find m
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  3. #3
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    wouldnt 5logm=10 be equivalent to log m^5=10
    and in that case m is not equal to 2.
    where am i going wrong?
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  4. #4
    Senior Member Stroodle's Avatar
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    log(x) usually means log_{10}(x)

    and

    log_a(b)=c\Rightarrow a^c=b
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  5. #5
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    Quote Originally Posted by way123 View Post
    wouldnt 5logm=10 be equivalent to log m^5=10
    and in that case m is not equal to 2.
    where am i going wrong?
    m does not equal 2 ... \log(m) = 2

    m = 10^2
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