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Math Help - Evaluating log

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    Evaluating log

    If log_b 6 = .4040 then b^-.4040 is equal to...I am not to sure about how to solve this.
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    Re: Evaluating log

    Quote Originally Posted by Bashyboy View Post
    If log_b 6 = .4040 then b^-.4040 is equal to...I am not to sure about how to solve this.
    If \log_b(X)=a then b^a=X~.
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    Re: Evaluating log

    Well, the exponent on b is negative, does that change the definition you gave me at all?
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    Re: Evaluating log

    Quote Originally Posted by Bashyboy View Post
    Well, the exponent on b is negative, does that change the definition you gave me at all?
    No indeed. It just requires one more step.

    If b^a=X then b^{-a}=\frac{1}{X}~.
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    Re: Evaluating log

    Oh, yes--I undserstand now. I do have another one, though: If log 2 = .3010 then log sqroot(20) is equal to.
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    Re: Evaluating log

    Quote Originally Posted by Bashyboy View Post
    Oh, yes--I undserstand now. I do have another one, though: If log 2 = .3010 then log sqroot(20) is equal to.
    First, you should start a new thread for a new question.

    Note that \log(\sqrt{a})=\tfrac{1}{2}\log(a).

    \log(20)=\log(10)+\log(2)

    Now contrary to modern trends it seems that here \log means \log_{10} so \log(10)=1.
    Last edited by Plato; December 18th 2011 at 04:56 PM.
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    Re: Evaluating log

    Do I sense condescension in your writing, or am I thoroughly mistaken?
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    Re: Evaluating log

    Quote Originally Posted by Bashyboy View Post
    Do I sense condescension in your writing, or am I thoroughly mistaken?
    You either have the largest chip on your shoulder or you can't read.
    Are you angry at me for not giving a complete and polished solution?
    Do you not want to learn how to do these?
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  9. #9
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    Re: Evaluating log

    No, I am absolutely not angry. I inferred that impression on my first reading of your post; but, after re-reading it, I have found that impression to be wrong. I am terrible sorry. I sensitive when it comes to scorning my mathematical knowledge; and I know it is scarce, due to myself having studied it a little later in life than normal, and that is why I was a bit jumpy. Again, sorry.
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