Arclength of the curve $y= \ln( \sec x)$ $ 0 \le x \le \pi/4$
I know that I have to find its derivative which is easy, it is $\tan x$
Then I put it into the arclength formula
$\int \sqrt {1 - \tan^2 x}$
From here I am not sure what to do, I put it in wolfram and it got something massive looking. I know I can't use u substitution and I am pretty certain I have to algebraicly manipulate this before I can continue but I do not know how.