Mathematica help

[PGI]

I have to evaluate some pretty messy derivatives using Mathematica. I would like to input ranges for the variables and to get a range (sign) for the expression (derivative). Can you, please, give me the explicit commands I can use to define the varible range (or domain) and get the expression range.

Thanks,

Peter

[somebody]

humm... lol i have taken my cal. course year ago so do not know what are you talking about without any question.. But hang on some one will come up with something