## mathcalculus 2 years ago DERIVATIVES: (attached below)

1. mathcalculus

2. Psymon

Now that's one that confuses me, too, lol x_x Not even sure what you're supposed to do with it. Curious to see what other people say.

3. Psymon

Oh, wait, I think it just wants the function?

4. mathcalculus

invite people.

5. mathcalculus

we can all use the help.

6. Yahoo!

Can We Use L-hospitals Rule ?

7. Psymon

Don't even know how to do that :P But the only thing I would be able to do is recognize that the function is x^(-3.25) and go from there. But that;d be cheating I think. And nah, l-hopitals rule is above his class.

8. mathcalculus

i don't know. it's a derivative question.

9. Psymon

L'hopitals rule is a calc II thing, so not much to worry about for yourself, lol.

10. Roya

If I were you i would use hopital phenomenal .

11. mathcalculus

yeah, no no hospital rule.

12. Psymon

Hehe, hospital rule.

13. chandanjha

differentiate both numerator n denominator with respect to h u got ur answer n put h =0

14. sami-21

I was thinking the same as Psyman mentioned that the original function is y=x^(-3.25) dy/dx=-3.25x^(-2.25) i guess in order to evaluate the limit Binomial expansion is required

15. chandanjha

simple l hopital rule wud do in this case

16. Psymon

I was thinking the expansion wasn't what the question really wanted, though.

17. sami-21

He is Just Newbie in the calculus I think He dont know L'Hôpital's rule !

18. Psymon

Yeah, he hasn't seen l'hopitals rule if he's just now doing this.

19. mathcalculus

SIGN: people who know this only.

20. CarlosGP

$\frac{ dx^p }{ dx }=\lim_{h \rightarrow 0}\frac{ (x+h)^p-x^p }{ h }=px^{p-1}$ And in this case p=-3.125

21. CarlosGP

Sorry, p=-3.25

22. CarlosGP

Then the solution:$-3.25x^{-4.25}$

23. sami-21

this is as mentioned above the derivative of the function $\Large y=x^{-3.25}$ using the power rule of derivative which states if $\Large y=x^n$ $\Large \frac{dy}{dx}=nx^{n-1}$ here n=3.25 just appply the power rule formula $\Large \frac{dy}{dx}=-3.25x^{(-3.25-1)}$ $\Huge \frac{dy}{dx}=-3.25x^{-4.25}$

24. Psymon

Yeah, more of just a knowledge of what the power rule for a derivative is and where within that difference quotient the original function actually is. In the end, it's the start of getting used to nx^(n-1) for derivatives :P