What is the domain of f (x) = 1 / sqrt((2 - x)(6 + x))?

1 Answer
Sep 17, 2015

x in (-6,2)

Explanation:

To be able to calculate f(x), we have to avoid dividing by 0 and to calculate square root of negative numbers. So,

(sqrt((2-x)(6+x))!=0 ^^ (2-x)(6+x)>=0) <=>
(2-x)(6+x)>0 <=>
(2-x>0 ^^ 6+x>0) vv (2-x<0 ^^ 6+x<0) <=>
(x<2 ^^ x> -6) vv (x>2 ^^ x< -6) <=>
x in (-6,2) vv x in O/ <=>
x in (-6,2)