Answer the following questions for the function
f(x)=x^3/(x^2−4)
defined on the interval [−19,16].
a.) Enter the x-coordinates of the vertical asymptotes of f(x) as a comma-separated list. That is, if there is just one value, give it; if there are more than one, enter them separated commas; and if there are none, enter NONE .
b)f(x) is concave up on the region=