www.piclist.com/techref/index.htm?key=brain+burp+rounding

> The fallacy in this argument is that at the end x->1, as any repeating

> number is not exact.

Wrong, all repeating fractions have an exact representation (they are

rational numbers). Only irrational numbers like PI have no exact

representation.

<rant on>

I consider, a complete understanding of rounding and number systems (very

basic algebra) to be absolutely essential for good engineering. In my

opinion, anyone involved in engineering of any sort should understand basic

algebra completely. Now, I'm not saying that all engineers must have this

info memorized but, they must have a gut feel for it and know where to look

up the precise info (e.g. their old text books).

<rant off>

In an attempt to help members learn the basics of algebra I searched the web

for some good references. However most of what I found was written for

children 13 years and younger (the authors expect the student to accept some

math principals on faith and, we all know that good engineers never accept

anything on faith :-).

I did find that James Brennan, professor of physics and mathematics at Boise

State University in the College of Applied Technology, has posted the

complete contents of his book "Understanding Algebra" online at:

http://www.edteach.com/algebra/

Read the "Decimals" section of Chapter 1 for info on rounding.

BTW - the subject of repeating fractions is also covered in that section.

For those who may have missed it the first time I posted it, here's a nice

web tutorial on significant figures and rounding by, Stephen

L. Morgan, Professor, Department of Chemistry & Biochemistry, The University

of South Carolina.

http://www.chem.sc.edu/faculty/morgan/sigfigs/index.html

Paul

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In reply to: <009701c0ea9f$4410b860$5dbdf682@AG.rl.ac.uk>

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