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Re: Why Indeterminate?

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  Re: Why Indeterminate? Themis Matsoukas <tmatsoukas@me.com> - 2011-05-02 10:53 +0000
    Re: Why Indeterminate? David Bailey <dave@removedbailey.co.uk> - 2011-05-03 09:44 +0000

#2034 — Re: Why Indeterminate?

The puzzling thing is that, having defined A and a, we now get

A[a, x]

(1/(1 - 3 (1 - 2 x)) + (2 (1 - 2 x))/(1 - 3 (1 - 2 x))) (1 - x) x

which has no indeterminacy. What Mathematica is not telling us is that it obtained this result assuming x<>0.5.

tm

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#2043

On 02/05/2011 11:53, Themis Matsoukas wrote:
> The puzzling thing is that, having defined A and a, we now get
>
> A[a, x]
>
> (1/(1 - 3 (1 - 2 x)) + (2 (1 - 2 x))/(1 - 3 (1 - 2 x))) (1 - x) x
>
> which has no indeterminacy. What Mathematica is not telling us is that it obtained this result assuming x<>0.5.
>
> tm
>

Imagine that Mathematica was as rigorous as you suggest. It could barely 
simplify any expression. For example,

(z^2+z)/z

could not be simplified without wrapping the result in a condition! 
Computer algebra (or indeed hand calculations) would be virtually 
useless done that way.

David Bailey
http://www.dbaileyconsultancy.co.uk

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