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From: "Joerg Buchholz" <buchholz@hs-bremen.de>
Newsgroups: comp.soft-sys.matlab
Subject: Re: int in R2008b, same integral?
Date: Sat, 13 Dec 2008 12:46:02 +0000 (UTC)
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"Georgios" 
> If you integrate using a bounded range, say -1..1, then you should get an answer of pi for both.  


Unfortunately, this is not the case:

>> int ('sqrt(1/(1-x^2))', -1, 1)
Warning: Explicit integral could not be found. 
> In sym.int at 64
  In char.int at 9
 
ans =
 
int((-1/(x^2 - 1))^(1/2), x = -1..1)

Even explicitely restricting the range of x does not help:

>> evalin (symengine, 'assume (x<1)');
>> evalin (symengine, 'assumeAlso (x>-1)');
>> evalin (symengine, 'getprop(x)')
 
ans =
 
(-1, 1)
 
>> int ('sqrt(1/(1-x^2))', -1, 1)
Warning: Explicit integral could not be found. 
> In sym.int at 64
  In char.int at 9
 
ans =
 
int((-1/(x^2 - 1))^(1/2), x = -1..1)