[Maxima] Half-angle-simplification of trig functions

[Stefano Ferri]

I hope you'll find soon where is the bug :-)... For me it would be quite 
important if assume worked fine, because I am writing a code in wich I 
need to know the sign of trigonometric functions, and as of now there is 
no way to do it with an assumptions over angles without explicitly 
declaring the sign of sin, cos, and the others functions. I use this 
workarond for now. Strange is also that there are analogous problems 
with %e...
Stefano

> Hello Stefano,
>
> Yes I think it is the same problem. 
>
> If I use an intervall (0,2*%pi) the simplification of sin(x/2) works well. If I
> use an intervall (0,%pi) the simplifcation of cos(x/2) works well. But now the
> simplification of sin(x/2) fails. If I use an intervall (0,3.0) both
> simplifications works well.
>
> I think this is a bug of assume with %pi as a value. I do not know the reason of
> the bug. I will have a deeper look into the code to find it.
>
> Dieter Kaiser
>