SOLUTION: Locate the critical points of the following function. Then use the second derivative test to determine whether they correspond to local maxima, local minima, or neither. f(x)=-x^3

Algebra ->  Test -> SOLUTION: Locate the critical points of the following function. Then use the second derivative test to determine whether they correspond to local maxima, local minima, or neither. f(x)=-x^3      Log On


   



Question 1155434: Locate the critical points of the following function. Then use the second derivative test to determine whether they correspond to local maxima, local minima, or neither.
f(x)=-x^3 -9x^2

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=-x^3-9x^2
f'(x)=-3x^2-18x
set equal to 0
3x^2-18x=0
3x^2+18x=0
3x(x+6)=0
0 and -6 are the critical points
f''(x)=-6x-18
when x=0 f''(x) is -18, so that is a maximum, local
when x=-6, f''(x)=18, so that is a minimum, local
graph%28300%2C300%2C-10%2C10%2C-1000%2C10%2C-x%5E3-9x%5E2%29