Anti-logs
By the way, if you know the log value and you want to find the original value of the number, how do you do it?
Use the anti-log, of course!! The antilogarithm (antilog) is the number corresponding to a given log so...
the log of 1000 is 3 ... therefore ...
1000 is the antilog of 3
However, if your calculator doesn't have an anti-log key, you can raise 10 to the log, or use the 10x key. For example, the log of the pollen diameter was −4.5, therefore the diameter in metres is
10−4.5 = 0.0000316 m
... which is the same as 3.16 x 10-5 m or 31.6 µm
If you are using Google as a calculator, type "10^−4.5 = " and hit "Enter".
How big is a fly's eye? The log of the diameter is −3.1...
(To make this problem interactive, turn on javascript!)
- I need a hint ... : Remember, the log is the exponent.
- ...another hint ... : Raise 10 to the log to get the original measurement back.
- ...another hint ... : Use the 10x key on your calculator, or type
"10^−3.1 = " on google.
I think I have the answer: 10−3.1 = 0.00080 m.
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