Question

Find the second derivative of the function.
f(x) = (ln(x))^9

Answer 1

9(lnx)^8 / x is the first derivative. Then you'll have to use quotient rule for the second derivative. derivative of the top multiplied by bottom term, minus derivative of the bottom multiplied by the top term, all divided by the bottom squared.

Answer 2

i am still a little confused on how to do that

Answer 3

I dont know wat i am suppose to do

Answer 4

Do you understand the first derivative?

The second derivative is then derivative of the top (72(lnx)^7) multiplied by the bottom (x).

72x(lnx)^7

Then subtract the derivative of the bottom multiplied by the top from this term.

1(9(lnx)^8)

Now you have

72x(lnx)^7-(9(lnx)^8)

Now divide all of this by the bottom squared (x^2)

final is just

72x(lnx)^7-(9(lnx)^8) / x^2


You can check wolfram alpha (a site) and it will show you the steps too if i did it wrong

Answer 5

I understand the first derivative. It is just when we have to find the second or third that i get confused at wat to do. thnxs for all ur help

Answer 6

i tried this answer and it is not accepting it. idk y it is doing that

Answer 7

I probably didn't do it right then lol, http://www.wolframalpha.com/input/?i=second+derivative+%28lnx%29%5E9 If you want the right answer here you go. (click show steps)

Answer 8

thnxs sooo much. This website will b a big help in the future!

Answer 9

You have no idea :P