Question

NEED HELP PLEASE...having problem solving.
given the function f(x)=3x^3-9x^2-2, find the coordinates of all the critical points of the function.

Answer 1

first differentiate

Answer 2

i did that and got 9x^2 - 18 = 0, but this where i'm stuck

Answer 3

i think the derivative of thefunction is not 9x^2 - 18 = 0,
but 9x^2-18x=0
x^2-2x=0
x(x-2)=0
x=2 and x=0

Answer 4

then plug the values of x to the function
f(0) = -2
f(2)= 3(2)^3 -9(2)^2 -2 = 24-36-2 = -14
so the critical points is (0,-2) and (2,-14)

Answer 5

oh ok. i got that! thanx alot