Local Max of f(x) Question

[killasnake]

Hi, I have a question with this problem do I just graph it and find the value of $\displaystyle x$? I am really not sure what to do the solve the problem.

At what value $\displaystyle x$ of does the local max of $\displaystyle f(x)$ occur?

$\displaystyle x$ =_____

 

[skeeter]

using the FTC ...

\(\displaystyle \L f'(x) = \frac{x^2 - 9}{1 + \cos^2{x}}\)

set f'(x) = 0 to find the critical values ... local max will occur where f'(x) changes sign from (+) to (-).