# question on derivative I wan chek

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• Dec 28th 2010, 12:25 AM
r-soy
question on derivative I wan chek
• Dec 28th 2010, 01:33 AM
chisigma
The computation is easier if You take into account the identity...

$\displaystyle \frac{\sqrt{s}-1}{\sqrt{s}+1} = 1 - \frac{2}{\sqrt{s} +1}$

Kind regards

$\chi$ $\sigma$
• Dec 28th 2010, 02:18 AM
r-soy
Is my answer no correct or not ?
• Dec 28th 2010, 03:34 AM
HallsofIvy
No, it isn't.

You have the formula $\left(\frac{u}{v}\right)'= \frac{u'v- uv'}{v^2}$ correct but then you used $\frac{uv'- u'v}{v^2}$ which is wrong.
• Dec 28th 2010, 04:04 AM
Prove It
Quote:

Originally Posted by chisigma
The computation is easier if You take into account the identity...

$\displaystyle \frac{\sqrt{s}-1}{\sqrt{s}+1} = 1 - \frac{3}{\sqrt{s} +1}$

Kind regards

$\chi$ $\sigma$

Actually it's $\displaystyle \frac{\sqrt{s} - 1}{\sqrt{s} + 1} = 1 - \frac{2}{\sqrt{s} + 1}$.