how can I simplify sqrt(1-sin(x)*sin(x)) to |cos(x)|



Yes, substpart can do this. Thanks a lot.

I alos get a different way inspired by your solution.

expr:sqrt(1-sin(x)*sin(x));
sqrt(trigsimp(expr^2));

2006/9/22, Stavros Macrakis <macrakis at gmail.com>:
> > I an new to maxiam, how can I simplify sqrt(1-sin(x)*sin(x)) to |cos(x)|
>
> Unfortunately, there is no completely automatic way to do this, but
> here are a couple of approaches.
>
> expr: sqrt(1-sin(x)*sin(x))$
>
> substpart(trigsimp(piece),expr,1);
>         Simplifies the part within the sqrt.
>
> substpart(trigrat(piece),expr,1);
>         Simplifies the part within the sqrt.
>
> trigrat(radcan(exponentialize(expr)));
>         Convert to exponential form, simplify the exponentials, and
> convert to trigonometric form.
>
> There are other approaches to try in other cases as well....
>
>              -s
>