On 4-7-09 Edwin Woollett wrote:
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The maxima function integrate(...) seems to know
something about "principal value", since a message is
printed to the screen, but integrate gets the wrong answer.
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another example:
(%i1) (fpprintprec:8,display2d:false)$
(%i2) integrate(1/(x^2 - 1),x,0,2);
Principal Value
(%o2) log(%i)-log(3)/2-log(-1)/2
(%i3) float(%);
(%o3) log(%i)-1.5707963*%i-0.549306
(%i4) ldefint(1/(x^2 - 1),x,0,2);
(%o4) -log(3)/2
(%i5) float(%);
(%o5) -0.549306
(%i6) quad_qawc(1/(1+x),x,1,0,2);
(%o6) [-0.549306,1.51336373E-11,105,0]
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Again integrate returns a wrong answer,
ldefint returns the right answer,
confirmed with quad_qawc.
Ted Woollett