df$^(\text{'}\text{'})($x$)=($e$^($x$)($x$^(2)-4$x$+6))/($x$^(4))($i$.$e$.$ take the second derivative and verify you have the correct

answer$).$ Find any point$($s$)$ of inflection and identify intervals in which f$($x$)$f$^(\text{'}\text{'})($x$),$ you should make use of the

discriminant to determine the types of roots. Don't forget to check where f$^(\text{'}\text{'})($x$)$ is undefined as

well!$\{$:f$^(\text{'}\text{'})($x$)=($e$^($x$)($x$^(2)-4$x$+6))/($x$^(4))\}$ pustient rule

List any point$($s$)$ of inflection:

List any interval$($s$)$ where f$($x$)$ is concave up:

List any interval$($s$)$ where f$($x$)$ is concave down: