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Topic: Low precision exponentiation
Replies: 5   Last Post: Feb 19, 2013 6:51 PM

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 Bob Hanlon Posts: 906 Registered: 10/29/11
Re: Low precision exponentiation
Posted: Feb 18, 2013 6:00 AM
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To avoid using machine precision enter exact numbers (Rationalize).
Exact result:

Rationalize[2.5]^125

2350988701644575015937473074444491355637331113544175043017503412556834518909454345703125/42535295865117307932921825928971026432

To a specified precision

N[%, 25]

5.527147875260444560247265192192255725514240233239`25.*^49

Bob Hanlon

On Sun, Feb 17, 2013 at 4:08 AM, Blaise F Egan <blaise@blaisefegan.me.uk> wrote:
> I am trying to evaluate 2.5^125 to high precision.
>
> R gives 5.527147875260445183346e+49 as the answer but Mathematica with N[2.5^125,30] gives 5.52715*10^49 and says that is to machine precision.
>
> I am inexperienced at Mathematica. Am I doing something silly?
>
> Blaise
>

Date Subject Author
2/18/13 Sseziwa Mukasa
2/18/13 Andrzej Kozlowski
2/18/13 Bob Hanlon
2/18/13 Murray Eisenberg
2/19/13 Dana DeLouis

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