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Math Help - logs?

  1. #1
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    logs?

    My teacher gave these two log questions to me, and I don't know how to do them. If someone could explain their answer it would help me out greatly.

    a) log'16 2 ("log subscript 16, 2")
    b) log'2 2"9 ("log subscript 2, 2 to the power of 9")

    Is there a program that will let me paste equations into the thread?
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  2. #2
    TD!
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    What do you think 'log' is and/or does? Do you know the definition?
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  3. #3
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    Log means what does the base needs to be raised to, to give your result?

    Thus,
    \log_{2} 16
    Means what does 2 have to be raised to to give 16? The answer is 4. Thus,
    \log_2 16 = 4
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  4. #4
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    I understand the definition. and I know that log(subscript 2) 16=4. I was just stuck with:

    a)log(subscript 16) 2=? , and
    b)log(subscript2) 2"(to power 9)=?

    -so A) is what do you raise 16 to, to get 2
    - and b) is what do you raise 2 to, to get 2 to the power 9? (I think)
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  5. #5
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    Quote Originally Posted by math619 View Post
    I understand the definition. and I know that log(subscript 2) 16=4. I was just stuck with:

    a)log(subscript 16) 2=? , and
    We need that,
    16^x = 2
    (2^4)^x=2
    2^{4x}=2^1
    4x=1
    x=1/4
    b)log(subscript2) 2"(to power 9)=?
    2^x=2^9
    x=9
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  6. #6
    TD!
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    Have you seen the following property?

    \log _a b = \frac{1}{{\log _b a}}
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  7. #7
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    No, I have not seen that before.

    so, if I have:

    a)log (subscript 7) 7

    that would equal 1?

    AND

    b)logs?-log.bmp

    that would equal 19?
    Attached Thumbnails Attached Thumbnails logs?-log.jpg  
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  8. #8
    TD!
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    Both answers are correct
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