ggFTW (http://ggftw.com/forum/)
-   Homework Help (http://ggftw.com/forum/homework-help/)
-   -   What is the first derivation of the following function (http://ggftw.com/forum/homework-help/119364-what-first-derivation-following-function.html)

 Degoutant 12-09-2012 11:15 AM

What is the first derivation of the following function

Hello people, here I am again!
I don't know how to derivate the following function.
http://omg.wthax.org/image_69.jpg
I guess we use the chain rule? No idea..
I'd appreciate help . Thanks in advance

 Nebula 12-09-2012 12:54 PM

Correct, you do use the chain rule!
You have probably just done a bunch of chain rule questions? The squareroot bit probably threw you off.
Try writing it as I have here.
http://i.imgur.com/ofeNd.png

Now, the first few lines I wrote the chainnrule in my notation. If it confuses you, let me know.

Next I have pointed out what the overall function is and the function inside the function part is. Now it is just a case of putting in the values. Once you have rewritten the squareroot like I have, it might make more sense to you.

Spoiler!

Checking can be done by using Wolfram Alpha, wolframalpha.com.

 Degoutant 12-17-2012 06:10 AM

Oh right, I totally forgot that the squareroot becomes ^1/2
thanks (sorry for the late reply)
http://omg.wthax.org/Foto.jpg
this should be it right?

 Nebula 12-17-2012 12:04 PM

It should be 1/2 (x^2+4x^(-4))^(-1/2)*(2x-16x^(-5))

If you can read that.
Do not forget to put brackets around the last part!
Sam with the bottom line. Otherwise it says something else.

The other part is the derivative of a squareroot is 1/2 of 1/the squareroot.

 Degoutant 12-26-2012 11:39 AM

Alright I'll try that out next time, sorry for my late response (ONCE again).

 All times are GMT -7. The time now is 08:31 AM.