Question

Find the absolute maximum and absolute minimum values of the function
f(x) = x^4 - 10 x^2 - 6
on each of the indicated intervals.


(A) Interval = [-3,-1].
Absolute maximum =

Absolute minimum =

(B) Interval = [-4,1].
Absolute maximum =

Absolute minimum =

(C) Interval = [-3,4].
Absolute maximum =

Absolute minimum =

i calculated the derivative to be 4x^3-20x
and factored out 4x to get
4x(x^2-5)=0
and got 1 critical point at sqrt(5) so i entered -sqrt5 on the absolute min for part and got it wrong and i dont know what the abs max would be for part a either