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Unformatted text preview: In fact we can
guarantee that, p ³0
regardless of the value of p.
We do need to be careful however to not misuse either of these definitions. For example we can’t
use the definition on x
because we don’t know the value of x.
Also, don’t make the mistake of assuming that absolute value just makes all minus signs into plus
signs. In other words, don’t make the following mistake, 4x  3 ¹ 4x + 3
This just isn’t true! If you aren’t sure that you believe that plug in a number for x. For example if
x = 1 we would get, 7 = 7 = 4 ( 1)  3 ¹ 4 ( 1) + 3 = 1
There are a couple of problems with this. First, the numbers are clearly not the same and so that’s
all we really need to prove that the two expressions aren’t the same. There is also the fact
however that the right number is negative and we will never get a negative value out of an
absolute value! That also will guarantee that these two expressions aren’t the same.
The definitions above are easy to apply if all we’ve got are numbers inside the absolute value
bars. However, once we put variables inside them we’ve got...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
 Spring '12
 MrVinh

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