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Student Support Forum: 'Bad Results when simplfying (?)' topicStudent Support Forum > General > Archives > "Bad Results when simplfying (?)"

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Juan J. Ruiz
01/31/05 04:02am

Hello:
It must be quite easy but I keep wondering why this happens. It is part of a bigger problem that I simplified for clarity.

My question is: Why the result of the following evaluation is cero?. It shouldn't!.
If you type and evaluate in Mathematica 5.0:

a=.;
b=.;
Simplify[1/Sqrt[(a-b)^2-(b-a)^2],(a > 0) && (b >0) && (a > b)]

Notice that the denominator vanishes.
The result given by Mathematica is zero!, however if you try:

x=.;
Simplify[1/Sqrt[(x)^2-(-x)^2],(x > 0)]

the result is ComplexInfinity and also gives an error, I like it! but not the first result.

Please, what is happening out there!

Can I trust Simplify[] and FullSimplify[]?

Thanks.



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Subject (listing for 'Bad Results when simplfying (?)')
Author Date Posted
Bad Results when simplfying (?) Juan J. Ruiz 01/31/05 04:02am
Re: Bad Results when simplfying (?) yehuda ben-s... 01/31/05 10:08am
Re: Bad Results when simplfying (?) Forum Modera... 01/31/05 10:28am
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