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Thread: Working with Logarithms?

  1. #1

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    Dazed Member
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    Question Working with Logarithms?

    Am i doing this correctly? 24 = 16 --> log2(2)4 = log216 --> 4 = log216

    And also i thought finding the root of a number was the inverse of an exponent? 52 = 25 --> Sqr(25) = 5

  2. #2
    Fanatic Member Gandalf_Grey_'s Avatar
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    yup, i am pretty sure anyways

  3. #3
    Fanatic Member bugzpodder's Avatar
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    The log question looks correct. by the way it should write x=logab --- and it says x is the power you put on a to get b.

    i think both a>0 and b>0 also a<>1

    And also i thought finding the root of a number was the inverse of an exponent? 52 = 25 --> Sqr(25) = 5
    depends on what you mean. if you are just talking about the sqrt(x) function, it says that we take the principal square root of x (or in other words, non-negative square root of x) so even though
    (-5)2=25 -->sqrt(25)=5 still
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  4. #4
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    I don't know if this helps but these are the basic rules of logarithms; they can't be argued against.

    1) If ab = c then b = logac (the logarithm of c to the base a)

    Denotations (these are the ones I use, but can differ from person to person):

    log10x = log(x)
    logex = ln(x)

    The following three apply to all logarithms, not just those with base 10:

    2) log(xn) = n.log(x) (that's n times log x)
    3) log(xy) = log(x) + log(y)
    4) log(x/y) = log(x) - log(y)

    Also:

    5) logaa = 1
    6) loga1 = 0 when a is not 1

    And if you want to convert one base logarithm to another:

    5) logba = logca / logcb
    6) logba = 1 / logab

    I hope this helps.

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