Question

Given f '(x) = (1 - x)(4 - x), determine the intervals on which f(x) is increasing or decreasing.

Answer 1

I got Decreasing (-∞, 1) U (4, ∞); increasing on (1, 4)

Answer 2

it might help to look at the graph of y = (1 - x)(4 - x)

Answer 3

recall that when f ' (x) is positive, f(x) is increasing

and when f ' (x) is negative, f(x) is decreasing

Answer 4

put in the easy x=0 value, it is +*+ a positive,

Answer 5

ok so I think it's decreasing (1, 4); increasing on (-∞, 1) U (4, ∞)

Answer 6

you nailed it

Answer 7

Thank you for your help!!

Answer 8

no problem

Answer 9

cubic with a positive leading term,