Question 824654:  Find the Domain 
f(x)=sqrt(x^2-4) 
x^2-4>=0 
x^2>=4 
Answer x>=2
 
These are the options to choose from and I'm not sure how to put it in this form. I don't know when to use () or []. 
[-2,2] 
[0,infinity) 
(-2,2) 
(-infinity,-2)U(2,infinity) 
[-infinity,-2]U[2,infinity] 
(0,infinity) 
[-infinity,-2)U(2,infinity] 
All real numbers 
None of these 
(-infinity,-2]U[2,infinity) 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! Find the Domain 
f(x)=sqrt(x^2-4) 
x^2-4>=0 
x^2>=4 
Answer x>=2 OR x<=-2 
------ 
(-oo,-2] U [2,+oo)
 
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Cheers, 
Stan H. 
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