Find the range in which the function f(x) = 8 + 40x3 5x4 4x5 is in

1.	Find the range in which the function f(x) = 8 + 40x3 5x4 4x5 is increasing.
A.	2<z<0, 0<z<3
B.	1<z<0, 0<z<2
C.	3<z<0, 0<z<2
D.	3<z<0, 0<z<4
Answer» D. 3<z<0, 0<z<4

Discussion