Question

How do you find the domain of `f(x) = 2 / (1 - x^2)`?

Answer 1

In this function you want to avoid values of `x` of the domain that makes the denominator equal to zero. So you need:
`1-x^2!=0`
And:
`x!=+-1`
So your domain will be all the real `x` except `+1` and `-1`.