Increasing and Decreasing Functions.

Question

Let f(x) = 4x^3 - 9x^2 -30x +6

A. Find all critical numbers of f(x)

B. Give the open intervals where f (x) is increasing and decreasing and clearly label each.

Answer 1

f' = 12x^2 - 18x - 30
Now use your Algebra I skills.

(A) the critical numbers are where f'=0

(B) f is increasing where f' > 0.