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| Science Forum Index » Education Forum » -- Wolfram Research QA process defect: Bug in... |
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Message |
| Vladimir Bondarenko... |
 Posted: Mon Mar 03, 2008 2:52 am |
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Guest
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-- NOT FIXED BUGS ARE DANGEROUS: THEY TEND TO GET MORE SEVERE --
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Quality of CASs is our #1 care.
So our little demo continues.... Hello again from the VM machine
which hopefully soon will be used by CAS manufacturers to the
benefit of their customers.
This example demonstrates YET ANOTHER case of bad defects in
Wolfram Research Quality Assurance process. Consider, it cannot
trap and fix efficiently bugs the long livers, even simple ones.
This is also an example of a MULTIPLE regression bug when the
invalid answer is now here, now not depending on the concrete
version.
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Just like our previous example, the following integral is
trivial, too.
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N[ Pi/4 ]
NIntegrate[ArcTan[Sqrt[z]]/(1+z)^2, {z, 0, Infinity}]
0.785398
0.785398
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Integrate[ArcTan[Sqrt[z]]/(1+z)^2, {z, 0, Infinity}]
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VERSION OUTPUT RESOLUTION
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Mathematica 6.0 0 <-------------------------------------- BUG
Mathematica 5.2 Pi/4 OK
Mathematica 4.2 0 <-------------------------------------- BUG
Mathematica 3.0 Pi/4 OK
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Derive is a $99 computer algebra system developed by Albert Rich
et al and acquired in 1999 by Texas Instruments. In Derive, the
customer just clicks and instantly sees the correct result.
Free fully functional 30 days trial (6.2 Mb, Win 98/ME/2000/XP)
http://derive.en.softonic.com/
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Derive 6.1 INT(ATAN(SQRT(z))/(z+1)^2,z,0,inf)
pi/4
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Maple 11.02> int(arctan(sqrt(z))/(1+z)^2, z=0..infinity);
1/4*Pi
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Best wishes,
Vladimir Bondarenko
VM and GEMM architect
Co-founder, CEO, Mathematical Director
http://www.cybertester.com/ Cyber Tester, LLC
http://maple.bug-list.org/ Maple Bugs Encyclopaedia
http://www.CAS-testing.org/ CAS Testing
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"We must understand that technologies
like these are the way of the future."
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