Inverse trigonometric functions



Lo?c wrote:
> Le dimanche 01 mars 2009 ? 11:20 -0800, Richard Fateman a ?crit :
>   
>> Lo?c wrote:
>>     
>>> Hello,
>>>
>>> Does anyone know if it's possible with Maxima to compute expressions
>>>   
>>>       
>> Please define what you mean by "compute expressions".
>>
>> Do you mean "prove that identities are true"
>> or do you mean "invent new formulas"
>> or do you mean confirm them numerically?
>>
>>     
>
> Why I write for example on some other computer algebra system:
> arctan(2)+arctan(5)+arctan(8) 
>
> it returns directly, or after a "simplify" command, the value 5*pi/4
>
>
>
> That's what I would like Maxima to do.
> Is it possible?
>   
Depending on what you mean by "example" some built-in simplification 
programs will do some of the work.
Otherwise you are free to write your own  new simplify command. You can 
also use something like the
Inverse Symbolic Calculator.

http://oldweb.cecm.sfu.ca/projects/ISC/ISCmain.html

But, basically, writing an algorithm that will ALWAYS find the smallest 
or "simplest" expression is
not possible unless you have a severely restricted class of expressions.