What is the derivative of the following function ?
Use the chain rule: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