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Math Help - Question About Logs

  1. #1
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    Question About Logs

    When I use a calculator to log 8, I get .903089986991944, and i am suppose to take four numbers after the decimal. So, I get .9030... However the answer is suppose to be .9031. I have noticed that a lot, the last number seems to always be 1 number lower(the 4th number after the decimal). Is that common?
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  2. #2
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    Re: Question About Logs

    The rule is: If asked for 4 decimal places look at the 5th figure. If it is 5 or more put the 4th number up by 1

    This example should explain. Write 3.68 correct to one decimal place. The answer is 3.7 because 3.68 is nearer to 3.7 than it is to 3.6
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  3. #3
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    Re: Question About Logs

    x = the number (.903089986991944)
    n = number of digits after decimal point (4)

    x = |x*10^n + .5| / 10^n ; that'll give you .9031

    By the way, your question has really nothing to do with logs;
    it's about "rounding".
    Last edited by Wilmer; April 21st 2012 at 10:11 AM.
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  4. #4
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    Re: Question About Logs

    Quote Originally Posted by biffboy View Post
    The rule is: If asked for 4 decimal places look at the 5th figure. If it is 5 or more put the 4th number up by 1

    This example should explain. Write 3.68 correct to one decimal place. The answer is 3.7 because 3.68 is nearer to 3.7 than it is to 3.6
    Ty
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