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Re: Low precision exponentiation

• To: mathgroup at smc.vnet.net
• Subject: [mg129849] Re: Low precision exponentiation
• From: Andrzej Kozlowski <akozlowski at gmail.com>
• Date: Mon, 18 Feb 2013 06:03:43 -0500 (EST)
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• References: <20130217090833.8CF776937@smc.vnet.net>

In Mathematica 2.5 is a machine precision number and applying N to it 
does nothing. You could use SetPrecision but a better way is to use 
exact input:

N[(5/2)^125,30]
5.52714787526044456024726519219*10^49

Andrzej Kozlowski


On 17 Feb 2013, at 10:08, Blaise F Egan <blaise at 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
>

• References:
  • Low precision exponentiation
    • From: Blaise F Egan <blaise@blaisefegan.me.uk>