From: SourceForge.net <noreply@so...>  20041026 09:35:40

Bugs item #1054472, was opened at 20041026 02:35 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1054472&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: defint(log(1+exp(A+B*cos(phi))),phi,0,%pi) wrong Initial Comment: Maxima 5.9.0 C1) assume(B>0,BA>0)$ (C2) integrate(log(1+exp(A+B*cos(phi))),phi,0,%pi);  B B A (D2) 3 %PI LOG(%E (%E + %E )) But if we give A and B numerical values (C3) B:3$ A:2$ ev(D2,numer); (C4) (C5) (D5) 2.952421848475173 (C6) B:3.2$ A:3$ ev(D2,numer); (C7) (C8) (D8) .0191075509605848 while by evaluating the integral numerically we obtain something different (C11) B:3$ A:2$ romberg(log(1+exp(A+B*cos(phi))),phi,0,%pi); (C12) (C13) (D13) 7.506856487627962 (C14) B:3.2$ A:3$ romberg(log(1+exp(A+B*cos(phi))),phi,0,%pi); (C15) (C16) (D16) 0.663669430006855 The integrand does not look like the kind of thing that would give the romberg procedure any trouble (C25) plot2d(log(1+exp(A+B*cos(phi))),[phi,0,%pi])$ In fact, by visual inspection of the plot it is clear that the area under the curve is much closer to 0.66 (romberg's result) than to 0.02 (as integrate would have us believe). The same problem occurs if we use defint instead of integrate. Cheers.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1054472&group_id=4933 