## anonymous one year ago Find the derivative of f(x) = -(9/x) at x = -8. How would I solve this?

1. anonymous

$-(\frac{ 9 }{ x })=-9x^{-1}$ Then use the power rule $\frac{ d }{ dx }x^n=nx^{n-1}$

2. UsukiDoll

either use quotient rule or the power rule

3. anonymous

Thanks guys. I think I get it

4. UsukiDoll

alright :)

5. anonymous

Can you tell me if I have the correct answer?

6. UsukiDoll

sure.

7. anonymous

8/9?

8. UsukiDoll

let me check.. I"m going to use power rule as @peachpi did

9. UsukiDoll

|dw:1437794741135:dw|

10. anonymous

9/64

11. zzr0ck3r

You mean find the derivative, not find the derivation. They are not the same thing :)

12. anonymous

got you

13. UsukiDoll

yeah ... if x = - 8|dw:1437794817385:dw|

14. UsukiDoll

whoa @zzr0ck3r scared me there XD