[Maxima] Bug in changevar. Should I submit the bug report?
toy.raymond at gmail.com
Thu Mar 22 10:58:50 CDT 2012
On Thu, Mar 22, 2012 at 7:30 AM, Robert Marik <marik at mendelu.cz> wrote:
> Dear all,
> I think that the following computation is a bug in changevar. Trying
> substitution cos(x)+sin(x)=t in integral of
> I get a mixture of function in t and x variable, see the output of (%o2).
This is most likely a failure in solve. I'm pretty sure changevar uses
solve to express x in terms of t, and solve(t=cos(x)+sin(x),x) -> [sin(x) =
t - cos(x)].
> The same is in version 5.24. Substutitution in
> (cos(x)+sin(x))^(1/6)*(-sin(x)+cos(x)) gives t^(1/6), as expected.
I don't follow here, but I guess you really meant cos(x)^(1/6)*sin(x), as
your example shows. This works because solve(t=cos(x),x) works.
> I was not able to find related bugreport. Should I open new one?
Yes, that would be very nice if you could. There's really no harm in
opening a new bug.
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