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-----Original Message-----
From: phys-l-bounces@mail.phys-l.org
[mailto:phys-l-bounces@mail.phys-l.org] On Behalf Of Brian Blais
Sent: Thursday, May 17, 2012 11:49 AM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] Conceptual Physics Course
On May 17, 2012, at 11:22 AM, Jeffrey Schnick wrote:
On a related note, what do you do to convince a person ina lasting
manner that the reciprocal of (1/x + 1/y) is not, in general, x+y?
x=y=0
x=y=one million
these two specific examples show that they aren't even close,
and can be done with just a little inspection. I try to get
my students to ask a few questions to themselves about any
term in an expression or an answer to a problem that they are
dealing with: is the answer greater or less than zero? is
the answer small or large compared to 1?
this allows them to catch many of the silly arithmetic errors
that they make, and would easily allow one to check the
expressions above.
bb
--
Brian Blais
bblais@bryant.edu
http://web.bryant.edu/~bblais
http://brianblais.wordpress.com/
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