OK, I WILL try & strive to do my best...

BTW By "Maxima list" is meant Maxima Google support group or something else?

On Tuesday, April 10, 2012 5:03:13 PM UTC+2, kcrisman wrote:
>
>
>
> On Saturday, April 7, 2012 1:49:22 PM UTC-4, Duc Trung Ha wrote:
>>
>> Hola,          
>>                
>> I was wondering about following eerie behavior of "solve" function:
>>                
>> On the one hand, "force" value of "to_poly_solve" option seems to be more
>> powerful as for periodicity of solutions:
>>                
>> sage: solve(tan(x)==1,x,to_poly_solve=True)
>> [x == 1/4*pi]
>> sage: solve(tan(x)==1,x,to_poly_solve="force")
>> [x == 1/4*pi + pi*z275]
>>                
>> On the other hand, "True" value of "to_poly_solve" occasionally gives out 
>> better outputs:
>>                
>> sage: solve(sin(x)/cos(x)-1,x,to_poly_solve=True)   
>> [x == 1/4*pi + pi*z299]
>> sage: solve(sin(x)/cos(x)-1,x,to_poly_solve="force")    
>> []             
>>                
>> However, "tan(x)==1" appears to me as an equivalent form of
>> "sin(x)/cos(x)-1==0".
>>  
>
>
> That's interesting.  I think that from our viewpoint, since we rely pretty 
> heavily on Maxima's `to_poly_solve` package at that point, the "right" 
> answer would be to
>  1)  find Maxima commands that would do the same thing (you'll have to 
> look a tiny bit at the source code for solve, available at 
> http://hg.sagemath.org/sage-main/file/c239be1054e0/sage/symbolic/expression.pyx#l7560and
>  further)
>  2) test them in the latest (5.27) Maxima
>  3) then pass it on to the Maxima list and in particular Barton Willis, 
> the author of this package, who would certainly be interested in anything 
> that would improve it.
> My guess is that in the first case, to_poly_solve has a way of converting 
> tan to something clever that then gets solved, but in the second case 
> doesn't and so returns the empty set of solutions ('force' makes 
> to_poly_solve the only way we try to solve an equation).
>
> If you could do this, I'm sure they would find it quite useful!  Thanks.
>

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