## pottersheep 2 years ago Please help! "challenge" calc question. We just learned power, product, chain rules...(I have to draw it out)

1. pottersheep

|dw:1360808280236:dw|

2. pottersheep

I must evaluate that

3. pottersheep

I don't know how :(

use the L'hopital hint : differentiate for the numerator and the denominator

5. pottersheep

We haven't learned questient rule if that is what you are saying?

6. pottersheep

quotient*

it just the derivative of a function... u can use the basic formula : y = x^n ----> y ' = n*x^(n-1) y = a (a is constant) ---> y ' = 0

8. pottersheep

I tried using product rule and I still got zeros in my denominator though

we neednt use the product or quotien here, just deriv each terms

derivative of x^1000 - 1 = ... ? derivative of x - 1 = .... ?

11. pottersheep

ohhh because what I did was I wrote it as (X^1000-1)(x-1)^-1

12. pottersheep

derivative of x^1000 - 1 = 1000x^999 derivative of x - 1 = 1?

13. pottersheep

What do I do now?

yes, that's right... now, just put x=1, u will get its answer

15. pottersheep

no quotient rule? :o

|dw:1360809016288:dw| NO QUOTIENT RULE :)

17. pottersheep

That's the right answer! Thank you, how come we dont have to use the quotient rule though if i have a fraction?

18. pottersheep

and there is division

sorry, icant explaind more... my english so bad :)

20. pottersheep

You're good at english I didnt even notice :) thank you for your time

you're welcome :)

22. SithsAndGiggles

I'll try to explain why the quotient rule isn't used. What @RadEn described was L'Hopital's rule, which says that the limit of some rational function f(x)/g(x) (a ratio of f to g), where both f and g are differentiable and g(x) is non-zero, is equal to the limit of the ratio of the derivatives of f and g. $\lim_{x\to c}\frac{f(x)}{g(x)}=\lim_{x\to c}\frac{f'(x)}{g'(x)}$ The quotient rule itself wasn't used because you do not find the derivative for f(x)/g(x), but rather f(x) and g(x) separately.

23. pottersheep

Ohhhhhhh thanks!!!