## anonymous 5 years ago how do i find the critical numbers for cube root of X+2 . I took the derivative of this and got (1)/[3(x+2)^(-2/3)]. is the next step setting this expression equal to 0?

1. anonymous

yes

2. anonymous

but Im having problem solving for 0 at this point.

3. anonymous

one sec

4. anonymous

and consider the x that will make the equation undefined as a critical number

5. anonymous

make the derivative i mean

6. anonymous

so I have to substitute a value for x that will make this expression ---> (1)/[3(x+2)^(-2/3)]. equal 0?

7. anonymous

8. anonymous

if I substitute -2 for x, the entire denominator equals 0. so would -2 b my critical number?

9. anonymous

yes you cant find a number that can make your derivative equal to 0 so -2 is the only critical number

10. anonymous

ohh okay!!! thanks a lot! :)

11. anonymous

@pineda isnt the derivative wrong?

12. anonymous

I think its right. I double checked it on my calculator

13. anonymous

it looks fine for me its $1/3\sqrt[3]{x+2^{2}}$

14. anonymous

is the equation $(x+2)^{3}$

15. anonymous

pineda100 is right

16. anonymous

its $\sqrt[3]{x+2}$

17. anonymous

yeah

18. anonymous

19. anonymous

^_^

20. anonymous

original equation is $\sqrt[3]{ }x+2$. sorry i coudlnt get the square root sign to appear completely

21. anonymous

ya then pineda is correct. my bad.

22. anonymous

okay thanks a lot for your help pineda and everyone else who contritbuted! much appreciated! :)