Find the domain of the function.

sqrt of x^2-9

The domain of a function is the set of all possible input values, which allows the function formula to work.

In this case when x ^2 > 9 then x ^ 2 -9 < 0

Square root negative numbers are complex numbers.

So domain of your function :

x ¡ 2 > 9

x > + OR - 3

thats mean

x <= - 3 and x >= 3

Becouse numbers less of - 3:

-4,-5,-6...

numers larger of 3:

4,5,6...

DOMAIN:

x <= - 3 and x >= 3

OR

(-infinity,-3) U (3,infinity)