find the domains of X+11/X^2+121

Question

find the domains of X+11/X^2+121

Answer 1

When you're finding the domain of a function, there are a couple of things you have to look out for:

1) You can't have a zero in the denominator of a fraction

2) You can't have a negative number under a square root (unless you're looking for an imaginary number...)

3) You can't take the log of a number less than or equal to 0.

 

For this function, it looks like we have to worry about case (1) - we can't have a zero in the denominator of a fraction.  When x = 0, we would get 11/0, which is not allowed.

 

Therefore, the domain of the function is that x does not equal 0. 

 

In interval notation, the domain would be: (negative infinity, 0) u (0,infinity).