33a 1 The function is decreasing on the interval It is incr

3-3a #1

The function is decreasing on the interval (,). It is increasing on the interval (,) and the interval (,). The function has a local maximum at.

Solution

f\'(x) = 6x^2 - 18x - 240 decreasing if f\'(x) < 0 i.e., x^2 - 3x -40 < 0 (x-8) *(x+ 5) < 0 decreasing on (-5,8) increasing on (-infinity,-5) and (8,infinity) maximum at x = -5