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Log[4]==2*Log[2]

• To: mathgroup at smc.vnet.net
• Subject: [mg50520] Log[4]==2*Log[2]
• From: Andreas Stahel <sha at hta-bi.bfh.ch>
• Date: Thu, 9 Sep 2004 05:17:32 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

To whom it may concern

the following answer of Mathematica 5.0 puzzeled me

Log[4]==2*Log[2]
leads to

N::meprec: Internal precision limit $MaxExtraPrecision = 50.` reached while \
evaluating -2\Log[2]+Log[4]

with the inputs given as answer. But the input

Log[4.0]==2*Log[2]

leads to a sound "True"

Simplify[Log[4]-2*Log[2]]
leads to the correct 0, but
Simplify[Log[4]-2*Log[2]==0]
yields no result

There must be some systematic behind thid surprising behaviour.
Could somebody give me a hint please

With best regards

Andreas
-- 
Andreas Stahel       E-Mail: Andreas.Stahel at [ANTI-SPAM]hti.bfh.ch
Mathematics, HTI     Phone: ++41 +32 32 16 258
Quellgasse 21        Fax:   ++41 +32 321 500
CH-2501 Biel         WWW:   www.hta-bi.bfh.ch/~sha
Switzerland

• Follow-Ups:
  • Re: Log[4]==2*Log[2]
    • From: Andrzej Kozlowski <andrzej@akikoz.net>