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 (-).