SOLUTION: f(x) = x^4 + 2x^3 - 252x^2 - 54 Find the interval(s) where f0(x) is decreasing.

Algebra ->  Finance -> SOLUTION: f(x) = x^4 + 2x^3 - 252x^2 - 54 Find the interval(s) where f0(x) is decreasing.      Log On


   

Question 864738: f(x) = x^4 + 2x^3 - 252x^2 - 54
Find the interval(s) where f0(x) is decreasing.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

f(x) = x^4 + 2x^3 - 252x^2 - 54

f' = x(4x^2 + 6x - 504) = x(4 - 42)(x  + 12)

x = -12, 0 , 10.5

f(x) is decreasing when x < -12   and  when 0 < x < 10.5