Question

can someone explain this math theorem to me? Please.

Answer 1

the function is between -x^2 and x^2

if you graph those two equations, you'll notice they intersect at (0,0)

because this function is always between them, it must also intersect at (0,0). It can't go above (0,0) or else it won't be between the two functions (same reasoning why it can't go below (0,0) either)

Answer 2

so you can't have f(x) approach 1 when x approaches 0