Calculation of simple Integrals



Lorenzo Isella wrote:
> Dear All,
> I am quite a newbie (I used maxima only a while several years ago),
> but there is something I find a biut strange:
...
> So, it looks like that maxima (as expected!) has no trouble in
> calculating definite integrals of simple trigonometric functions, but
> if I add an absolute value, even if it has no effect on the sinus in
> the selected interval, then it returns what (according to some reading
> I did) stands for its inability of calculating the integral
> analytically.
> Why is that? Am I misunderstanding anything?
> Kind Regards

When you do abs(sin(x))^2 maxima is able to figure out that the abs 
doesn't make a difference, but when you do abs(sin(x)) the abs could 
make a difference. Now maxima has to find out where are all the places 
that the argument of abs changes sign... Although for some functions 
this is easy, in general it is impossible. Maxima doesn't try very hard 
on this impossible problem although it could try for some easy sorts of 
functions.