What is the logarythm called?

Question

I know that lnx is log e x (just found out today!)
Up until today I thought lnx is log10 x.Is there a special notation for logarithm in base 10?
Why was I confused for so long? :)

Answer 1

I've been involved with discussions on science-related bulletin-boards, even in the past year, on just this subject.

Some cultures think, just as you, that ln(x) means log10(x). I was 'raised' with ln(x) as loge(x), and log(x) as log10(x).

Through this latest discussion thread last year, we all came to learn that there is no proper authoritative standard for the notation, but the vast majority of us learned it the way I was raised: ln(x) is loge(x), and log(x) is log10(x).

If this is how your textbook uses it (and your teacher) then you should do it that way. But be aware, in the future, you might see it in a book or paper, again, the way you had always thought it was to be.

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Answer 2

In engineering, they call it a common or simple log.

The notation is usually log10x = lg(x)

From Wikipedia, "Mathematicians generally understand both "ln(x)" and "log(x)" to mean loge(x) and write "log10(x)" when the base-10 logarithm of x is intended. Calculus textbooks will occasionally write "lg(x)" to represent "log10(x)". "

Answer 3

It is accepted convention that if a log has no stated base, it is base 10. (Imagine if we had to question every written number as to its base: Is 1101 one thousand one hundred one or is it thirteen base 2)

Ln is natural log, that is Log (base e).