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#1
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Logarithms
Hello,
How can I divide a logarithm by a logarithm? For example, I would like to make the following computation in one cell: = log10(number) / log10(number) I know I can take the log of the numerator in one cell and the denominator in another, however, this is not what I want. Please advise |
#2
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Logarithms
=LOG10(A1)/LOG10(A2)
Tim -- Tim Williams Palo Alto, CA "sirsoto" wrote in message ... Hello, How can I divide a logarithm by a logarithm? For example, I would like to make the following computation in one cell: = log10(number) / log10(number) I know I can take the log of the numerator in one cell and the denominator in another, however, this is not what I want. Please advise |
#3
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Logarithms
If by Log10(number) you mean Log (number) to base 10, then =Log(A1)/Log(B1) in your chosen cell. -- davidm ------------------------------------------------------------------------ davidm's Profile: http://www.excelforum.com/member.php...o&userid=20645 View this thread: http://www.excelforum.com/showthread...hreadid=388201 |
#4
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Logarithms
Thanks for responding. I tried it but it didn't work. In cell A1, I typed
the following: =log( ( ((300000*.05)+1) / (150*49) ) /log(1.05) ) i only put the spaces here for your ease of reading. The result should equal a non-integer, 22.0918475. I did it by hand, so i know this value is correct. |
#5
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Logarithms
Did Excel give you an answer of about 0.027? I tried it by hand and got around 0.027. I copied and pasted what yo wrote without the spaces into Excel and got around 1.98. I entered th different sets of the problem individually into Excel and got th correct answer of 0.027 again -- Loss ----------------------------------------------------------------------- Losse's Profile: http://www.excelforum.com/member.php...fo&userid=2481 View this thread: http://www.excelforum.com/showthread.php?threadid=38820 |
#6
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Logarithms
Excel knows the correct order of operations. As soon as you close the )'s, the log entry is complete. You can try: =LOG(1+300000*0.05)/(150*49) /LOG(1.05) to get the correct answer of around 0.27 -- Losse ------------------------------------------------------------------------ Losse's Profile: http://www.excelforum.com/member.php...o&userid=24813 View this thread: http://www.excelforum.com/showthread...hreadid=388201 |
#7
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Logarithms
Not sure how you got 22.1 as the answer. I can't come up with 22.1. The correct answer as written is 1.98. log( ( ((300000*.05)+1) / (150*49) ) /log(1.05) ) =log( (15000+1) / 7350 / log(1.05) ) =log(15001/7350/log(1.05)) =log( 2.04 / 0.021) = log(96.3) = 1.98 Losse's interpretation of what you wanted does evaluate to 0.027, but note that he changed the groupings so it isn't the exact same formula as you posted. log(15001)/7350/log(1.05)= 4.18/7350/.021=.027 I expect that, with all those parantheses, there is some confusion as to what exactly you want to take the logarithm of and what should not, and overall where the parantheses should be. -- MrShorty ------------------------------------------------------------------------ MrShorty's Profile: http://www.excelforum.com/member.php...o&userid=22181 View this thread: http://www.excelforum.com/showthread...hreadid=388201 |
#8
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Logarithms
Why don't you post it again using brackets to distinguish the area fo the log -- Loss ----------------------------------------------------------------------- Losse's Profile: http://www.excelforum.com/member.php...fo&userid=2481 View this thread: http://www.excelforum.com/showthread.php?threadid=38820 |
#9
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Logarithms
here in Excel what are logarithms for? what specific jobs could this be
applicable to? thanx |
#10
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Logarithms
l.a.: logarithms show up frequently in math, science, and engineering calculations. Basically, a logarithm is the "inverse" of exponentiation [10^3=1000, log10(1000)=3]. There are several good tutorials on logarithms on the internet - try putting "logarithm" into your favorite search engine. -- MrShorty ------------------------------------------------------------------------ MrShorty's Profile: http://www.excelforum.com/member.php...o&userid=22181 View this thread: http://www.excelforum.com/showthread...hreadid=388201 |
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