Thank you for the explanation. I missed the related discussion on the
mailing list. I had no idea that the old behaviour could cause such
problems.
Anyway, given, for example, 2^(5/2), is there the possibility to let
Maxima rewrite it to 4*sqrt(2) or, as I can imagine, Maxima
automatically doesn't allow this?
Mine was simply an "aesthetic" issue, because I would like to see some
final results of the computation in the form something*sqrt(something
else), with integer powers separeted form fractional ones. But it's
not a problem!
Thank you
Stefano
2009/8/30 Dieter Kaiser <drdieterkaiser at web.de>:
> Am Sonntag, den 30.08.2009, 14:58 +0200 schrieb Stefano Ferri:
>> Is something changes in Maxima handling of powers? In older versions I got
>> this:
>>
>> (%i1) 4*sqrt(2);
>> (%o1) 4*sqrt(2)
>> (%i2) 6*sqrt(2);
>> (%o2) 6*sqrt(2)
>>
>>
>> while in ?Maxima 5.19.1 I get:
>>
>> (%i1) 4*sqrt(2);
>> (%o1) 2^(5/2)
>> (%i2) 6*sqrt(2);
>> (%o2) 3*2^(3/2)
>>
>> I don't want sqrt(2) to be merged with integer powers of 2. I would like to
>> see 4*sqrt(2) and 6*sqrt(2) instead of 2^(5/2) and 3*2^(3/2). Is there a
>> command to do this?
>
> Yes, the behavior has changed because of revision 1.80 of simp.lisp. We
> had a longer discussion on the mailing list about this topic.
>
> The handling of powers of integers has been implemented in a more
> consistent way. This solved e.g. the following problems which have been
> declared to be a bug:
>
> ? BUG ID: 721575 2/sqrt(2) doesn\'t simplify
> ? BUG ID: 2029041 a*sqrt(2)/2 unsimplified
> ? BUG ID: 1923119 1/sqrt(8)-sqrt(8)/8
> ? BUG ID: 1927178 integrate(sin(t),t,%pi/4,3*%pi/4)
> ? BUG ID: 1480562 2*a*2^k isn't simplified to a*2^(k+1)
> ? BUG ID: 1853191 rat(2/sqrt(2)),algebraic doesn't cancel
> ? BUG ID: 1996354 unsimplifed result from expand
>
> Please try the following input with an older version and you will see
> the following results:
>
> ?sqrt(2)*2 ?--> 2^(3/2)
> ?sqrt(2)*4 ?--> 2^(5/2)
> ?sqrt(2)*6 ?--> 3*2^(3/2)
>
> You see that 2*sqrt(2) and sqrt(2)*2 are simplified differently in older
> versions. This causes a lot of simplification problems. Both expressions
> 2*sqrt(2) and sqrt(2)*2 now simplifies to the same expression 2^(3/2).
>
> Dieter Kaiser
>
>
>