6 + 3x - x3 intervals of increase. So far I got the critical numbers to be 1 and -1. I think this increases from -infin to -1. and decreases from -1,1. then increases again from 1 to infinity. '
Is this right?

Question

6 + 3x - x3 intervals of increase.  So far I got the critical numbers to be 1 and -1. I think this increases from -infin to -1. and decreases from -1,1. then increases again from 1 to infinity. '
Is this right?

anonymous · Answer

I think you have to differentiate and equate it to zero or something!

jhonyy9 · Answer

- so you need to check it for :
- x=-1 --- 6-3(-1)-1*3=6+3-1=8
   x=-2 --- 6-6-8=-8
   x=0 --- 6+0-0 =6
   x=1 --- 6+3-1=8 
- so you can see that is true exactly how you have wrote it.