TideMan <email@example.com> wrote in message <firstname.lastname@example.org>... > On Tuesday, December 17, 2013 3:40:18 PM UTC+13, Nikola Kal wrote: > > First of all sorry because of my bad English :) > > > > > > > > How can i get domain of function? > > > > For example domain of function sqrt(x-3) is x>=3 > > > > Or domain of function log(x-1) is x>1 etc. > > > > Thank you for all help... > > Matlab is quite happy evaluating log(-1) or sqrt(-3) or even log(-inf). > So, the domain for these functions is infinite. > > So I guess what you mean is, you want the REAL domain? > Yes, i'm looking for real domain. There are examples: 1.domain of function sqrt(x-3) is x>=3 2.domain of function log(x-1) is x>1 3.domain of function asin(x+1) is -1<=x+1<=1 4.domain of function acos(3*x+1) is -1<=3*x+1<=1, etc. So, if you understand can you help me? Big thanks in advance.