Proble : maxima finds a primitive, but not a defnite integral.



Dear list,

Could some kind soul explain to me why maxima

Maxima 5.28.0 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.7 (a.k.a. GCL)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.

can easly find this primitive :

(%i1) integrate(1/(1+sqrt(x)), x);
(%o1)                2 (sqrt(x) + 1) - 2 log(sqrt(x) + 1)

but does not appy it to this definite integral :

(%i2) integrate(1/(1+sqrt(x)), x, 0, 1);
                                1
                               /
                               [       1
(%o2)                          I  ----------- dx
                               ]  sqrt(x) + 1
                               /
                                0

In other words, WTF ???

Sincerely,

					Emmanuel Charpentier
					DDS, MSc, stymied...

PS : an, oh, by the way quad_qags

(%i5) quad_qags(1/(1+sqrt(x)), x, 0, 1);
(%o5)         [0.61370563888011, 2.5191337904573174E-10, 231, 0]

seems preferable to quad_qag

(%i6) quad_qag(1/(1+sqrt(x)), x, 0, 1, 6);
(%o6)          [0.6137056388632, 3.5930198130608816E-9, 1159, 0]

In this example. Again, why ?