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HP Forum Archive 09

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CAS bug?
Message #1 Posted by mapet on 22 Nov 2002, 6:39 a.m.

Tan(x)integral from 0 to oo crashes my HP 40G. How about Hp 49G ?

      
Re: CAS bug?
Message #2 Posted by Tom Sherman (Maine) on 22 Nov 2002, 9:31 a.m.,
in response to message #1 by mapet

I am crashing too!! What can the integral of sin, cos, or tan be, when integrated to infinity? Maybe Lewis Carroll could tell me.

            
Re: CAS bug?
Message #3 Posted by axel on 22 Nov 2002, 10:05 a.m.,
in response to message #2 by Tom Sherman (Maine)

Integral of Tan(x) is -ln(cos(x)) which has a singularity at x=pi/2 (and 3/2 pi, 5/2 pi etc). So the integral from 0 to x=pi/2 would be oo. Although, you can calculate the Cauchy principal value (limit for x-> pi/2) of the integral from 0 to pi, which is 0. Hopefully not to confusing eplained...

Greetings from Jena, Germany

                  
Re: CAS bug?
Message #4 Posted by Vieira, Luiz C. (Brazil) on 22 Nov 2002, 11:06 a.m.,
in response to message #3 by axel

Hi;

would this singularity raise to oo if PI/2 is not exact? Is the exact-mode flag set? What about trying in Approximate mode?

I did not try it, but I thought I could suggest it.

Regards from Brazil.


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