Question

Someone please help I don't get none of this :\

Answer 1

The function $f(x)=x^2-2$ is defined for every real number (It is a polynomial function).

But we have :
$\forall x\in\mathbb R,\quad x^2\ge0$

so :

$\forall x\in\mathbb R,\quad x^2-2\ge-2$


Therefore ;

domain of f is all real number , range of is y≥-2

domain of f^-1 is x≥-2 , range of f^-1 is all real number