Re: Request for Assistance on Logs/Anti-LOGS
[Prev][Next][Index][Thread]
Re: Request for Assistance on Logs/Anti-LOGS
----- Original Message -----
From: Ray Kremer <raykremer@HOTMAIL.COM>
Subject: Re: Request for Assistance on Logs/Anti-LOGS
> I'm amused how often this gets asked. Since logarithms are really inverse
> exponents,
No. Logs ARE exponents. Just read the definition of (base 10) log:
log(x) = y if and only if x=10^y
The y in the left equation is what the log equals; in the right equation, it
is an exponent. So logs are exponents. And they obey exponent laws, in their
own special ways.
I think you mean that logs are really inverses of exponentIAL FUNCTIONS. Big
difference. I'm not sure what an "inverse exponent" is. Could be a root.
It's NOT a commonly used phrase, in my books.
>the inverse of a logarithm should be apparent. Whoever came up
> with the term "antilog" should be shot, it just confuses people.
When we had to use log tables, "anti" made some sense, as you were going
backwards (against the "normal" flow of the log table). I almost want to say
that the term is, indeed, now worthless, BUT it is that same "backward"
sense that makes it seem like finding an antilog is, indeed, using the
inverse function relationship, especially when looking at a graph of
y=log(x), so maybe the TERM is archaic, but the CONCEPT isn't.
> like asking how to find the inverse of the Arcsin.
The inverse of the arcsin (another archaic term which I nevertheless think
is no more confusing than writing "inverse sine" as something that looks
like "sin^(-1)") function is the sine function. I don't see how this is like
asking what is an antilog.
I reiterate:
> >Since y=log x and x=10^y are different representations of the SAME
> functions
> >(using the definition of log) and
> >since x=10^y and y=10^x are INVERSE functions,
> >then y=log x and y=10^x are inverses of each other,
> >so antilog(x)=10^x
By the way, the original question was, "What is an antilog?" and "How do I
find it on my TI?". The above 6 lines answer that question logically, if you
consider another line I wrote:
"antilogs would be more appropriately called inverse logs"
MY question is, "What current textbook is still calling exponential
functions antilogs??"
Dave Slomer
Greenhills, OH
davidslomer@geocities.com
http://www.geocities.com/CapeCanaveral/Lab/8692/
******************************************************************
* To UNSUBSCRIBE, send an email TO: listserv@lists.ppp.ti.com
* with a message (not the subject) that reads SIGNOFF CALC-TI
*
* Archives at http://peach.ease.lsoft.com/archives/calc-ti.html
******************************************************************
Follow-Ups:
References: