point of inflection of y=(x^3)/(x^2+4)

[ssabadnama3]

find the point of inflection of y=(x^3)/(x^2+4). im not sure on the 2nd derivative test wether to find critical points from both derivatives and use them or just the first

 

[mmm4444bot]

You only need the critical point(s) for the second derivative because you're looking for where the second derivative changes sign.

CLICK HERE for a review.