Another integration bug may related to
r1156:
f2:=
1/(x^3+3*x^2+3*x)/(x^3+3*x^2+3*x+3)^(1/3)
integrate(f2,
x)
In Fricas 1.1.3 (release before r1156), the integration seems
timeout,
in Fricas 1.1.4 (release after r1156) to trunk version,
this
integration
returns:
>> Error detected within library
code:
impossible
I can confirm this error message comes from 'palglogint'
in
intalg.spad (which is introduced in
r1156):
https://github.com/fricas/fricas/blob/master/src/algebra/intalg.spad#L443
This integral comes
from
http://12000.org/my_notes/CAS_integration_tests/test_cases/timofeev/resu32.htm#319
The answer is
g2:
t:=
(x^3+3*x^2+3*x+3)^(1/3)
c1:=3^(1/3)
g2:=-log(t^3-3)/6/c1+log(c1*(x+1)-t)/2/c1-atan((t+2*c1*(x+1))/sqrt(3)/t)/3^(5/6)
By the way, there are 11 lines of 'error "impossible"' scattered in
8
files, should we change the error message to contain its function
name
to help users report the
bug?
And Waldek, when you make the r1156 changes, are you based on
an
article or a book?
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