What is the derivative of the following function ?

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- Apr 11th 2006, 11:53 AMtotalnewbieDerivative
What is the derivative of the following function ?

- Apr 11th 2006, 01:11 PMCaptainBlackQuote:

Originally Posted by**totalnewbie**

If:

$\displaystyle

y=f(g(x))

$

then:

$\displaystyle

\frac{dy}{dx}=f'(g(x))\ g'(x)

$

In this case $\displaystyle f(u)=\ln(u)$ and $\displaystyle g(u)=u^2+1$, so:

$\displaystyle

\frac{d}{dx}\ \ln(x^2+1) = \frac{1}{x^2+1}\ 2x=\frac{2x}{x^2+1}

$

RonL