richard noel fell <fell at brandeis.edu> writes:
> With maxima 5.29.1 I find the following bug:
> (%i1) int1:z*(1-z)*log(1-a^2*z*(1-z));
I'm sorry, but I don't have 5.29.1 to hand. I've tried your example with
version 5.30. There, I got asked the sign of a three times in a row
(bug, but not disastrous) and eventually got given an answer. With the
current master tree, I got
(%i22) int1:z*(1-z)*log(1-a^2*z*(1-z));
2
(%o22) (1 - z) z log(1 - a (1 - z) z)
(%i23) integrate(int1,z,0,1);
Is a - 2 positive or negative?
neg;
(%o23) {something with atan's and sqrt's}
That result looked reasonably sensible.
> (%i2) integrate(int1,z,0,1);
> subst: cannot substitute - z for operator z in expression z(1 - z)
> -- an error. To debug this try: debugmode(true);
This is weird: it looks an awful lot like you typed "z(1-z)" rather than
z*(1-z). Then Maxima is trying to replace z with -z deep inside an
integration routine and it gets confused because the first "z" in
"z(1-z)" is interpreted as a function (or "operator") and it doesn't
know how to replace it. Could you have mistyped something?
> (%i4) integrate(int1,z,0,1);
> Is a positive or negative?
>
> p;
> Is a - 2 positive or negative?
>
> n;
> file_search1: trgsmp.mac not found in file_search_maxima,system.
Eek. That looks bad. Are you sure that your Maxima installation is
complete? I'd probably advise reinstalling to make sure, but you could
also look to check that trgsmp.mac is in a directory looking something
like
path-to-maxima-install-dir/5.29.1/share/trigonometry/trgsmp.mac
Rupert
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