Question

How do you find the domain of `y = (3x^2)/(x^2+1)`?

Answer 1

The domain is all the Real `x`.

Explanation:

The only problem with this function would be a value of `x` that makes it a division by zero; but the denominator will never become zero!
There is no Real value of `x` that makes `x^2+1` equal to zero.

`x^2+1=0` or `x^2=-1` NEVER

So this function can accept all the Real `x`.