help with critical points

• February 22nd 2010, 08:31 PM
vinson24
help with critical points
Find all the critical points
$f'(x)=ln(2/(1+x^{2}))$
I know you set the equation to 0
$0=ln(2/(1+x^{2}))$ but not sure how to solve it
• February 22nd 2010, 10:42 PM
CaptainBlack
Quote:

Originally Posted by vinson24
Find all the critical points
$f'(x)=\ln(2/(1+x^{2}))$
I know you set the equation to 0
$0=\ln(2/(1+x^{2}))$ but not sure how to solve it

$\ln\left(\frac{2}{1+x^{2}}\right)=\ln(2) -\ln(1+x^2)=0$

So the critical points are the roots of:

$\ln(1+x^2)=\ln(2)$

or of:

$1+x^2=2$

CB