
#1
Jul3008, 05:37 PM

P: 884

Hi!
We have 3 functions; f=, g=[tex]\frac{1}{\sqrt{(2x2  1)(x21)}}[/tex] and h= [tex]\frac{\sqrt{2+x}+x(x^21)}{(x^21).\sqrt{2+x}}[/tex] And we want to write the domain of these functions in the set builder notation, which I'm not very familiar with. Well, I know that for the Domain of g, x ≠ 0 and ±1. How do we write it in that notation? is it [0,∞]\{±1}? For the domain of f, x must be greater than or equal to 2 and it cannot equal 0 & ±1 In h, domain: x≥2, & it can't be ±1 as well. I need to write the domains of these functions in the set builder notation. Not knowing something doesn't mean you're stupid, just asking about it ... 



#2
Jul3008, 06:22 PM

Sci Advisor
HW Helper
P: 1,276

You could write the domain of x as [2,∞)\{0,±1}
or as Dom(f) = {x x [itex]\in[/itex] [2,∞)\{0,±1}} Make sense? Notice the open parentheses on the infinity, since x cannot actually infinity (as it is not a number) 



#3
Jul3008, 07:01 PM

P: 884

OK, Nick. How should I express the domains of g and h?
Where g = [tex]\frac{1}{\sqrt{(2x^2  1)(x^21)}}[/tex] Would the domain of g be written as: dom(g)= R\{0, ±1} ? And... how would the domain of h be in this notation? 



#4
Jul3008, 07:57 PM

Sci Advisor
HW Helper
P: 1,276

Set Builder Notation
Yes that would be a way to write the domain of g.
For h you could write Dom(h) = [2,∞)\{±1} 



#5
Jul3008, 08:09 PM

P: 884

Right
Thanks a lot! Makes sense now... 


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