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Interval arithmetic bug

• To: mathgroup at smc.vnet.net
• Subject: [mg90761] Interval arithmetic bug
• From: green tea <cetech07 at gmail.com>
• Date: Wed, 23 Jul 2008 05:58:04 -0400 (EDT)

In[1]:= Limit[Sin[x], x -> Infinity]

Out[1]= Interval[{-1, 1}]




In[2]:= Limit[Sin[x + Pi/4], x -> Infinity]

Out[2]= Interval[{-Sqrt[2], Sqrt[2]}]




In[3]:= TrigExpand[Sin[x + Pi/4]]

Out[3]= Cos[x]/Sqrt[2] + Sin[x]/Sqrt[2]




In[4]:= (Limit[#1, x -> Infinity] & ) /@ {Cos[x]/Sqrt[2],
  Sin[x]/Sqrt[2]}

Out[4]= {Interval[{-(1/Sqrt[2]), 1/Sqrt[2]}],
   Interval[{-(1/Sqrt[2]), 1/Sqrt[2]}]}




In[5]:= Plus @@ %

Out[5]= Interval[{-Sqrt[2], Sqrt[2]}]




In[6]:= $Version

Out[6]= "6.0 for Microsoft Windows (32-bit) (May 21, 2008)"




oh my god..

• Follow-Ups:
  • Re: Interval arithmetic bug
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>