Question

When is 2x/((1+x^2)^2) undefined? I know a function is undefined when the denominator is = 0, but I keep getting imaginary numbers like sqrt -1...

Answer 1

when ((1+x^2)^2)) is = to zero ya?
and the only time something squared is 0 is then that something is 0
so 1+x^2 =0
x^2 is always positive (or zero) so the function is always defined

Answer 2

Thank you!

Answer 3

if it was ((1-x^2)^2

changed that to minus then you would have an undefined part