If #f(x) = 2x^3 + 3x^2  180x#, how do I find the intervals on which f is increasing and decreasing?
1 Answer
Feb 19, 2015
Hello,
1) You have to calculate the derivative :
2) Solve
Therefore,
3) You can now study the sign of
#f'(x) <0 iff x \in ]6,5[# .#f'(x) >0 iff x\in ]oo , 6[\cup ]5,+oo[# .
4) Conclusion :

