EXERCISES

$7\mathrm{.}1.$ In each example below, $f$ is given either as a rule or as a set of ordered pairs. In each case, determine whether or not $f$ is a function from $S$ to $T.$ For those cases in which it is$,$ determine whether it is one$-$to$-$one, and whether it is onto.

d$)S=T=R,f(x)=x^2-x$

e$)S=T=R,f(x)=x^3$

f$)S=T=R,f(x)=\sqrt[\phantom{2}]{x}$