In: Math
Let f(x)=−(3x^3+8)
(a) List the critical point(s) of f=
(b) f′(x)>0f′(x)>0 for x∈=
(c) f′(x)<0f′(x)<0 for x∈=
Note: the answers to the above questions can be a value, a list of values, an interval, a union of intervals, or "NONE" if no values exist.