Question

Could I use "square root of -1" to determine domain if all my x-values in the function are squared? Example inside.

Answer 1

Suppose the function is \[\frac{ 2x^2-1 }{ x^2+1 }\]
The equation is undefined where the denominator =0. If I put -1 in for x, the square makes it +1, and the denominator will be 2. But if I set x=sqrt(-1), the sqaure cancels the root, and I'm left with -1, which makes the denominator zero, and the function undefined. Can I do this?