18. Five marks exercise problems III

If $f: \mathbb{R} \rightarrow \mathbb{R}$ and $g: \mathbb{R} \rightarrow \mathbb{R}$ are defined by $f(x) = x^5$ and $g(x) = x^4$ determine whether $f$, $g$ are one-to-one and $f \circ g$ is one-to-one?

 

$f$ is one-to-onenot one-to-one.

 

$g$ is one-to-onenot one-to-one.

 

$f \circ g$ is one-to-onenot one-to-one.