At the risk of looking dumb....

- ln (cos (Pi/4) )

I know the cos part is square root of 2 over 2. I think I vaguely remember the details of that. The answer was written as 1/2 ln 2. Why/how? For some reason I'm not remembering anything that gets me to that point.

This was part of a larger problem. I'm just stuck at that final part. And what should I review related to that?

Ugh. It's like I forgot everything. So this past week I have gone through all my calc 1 notes and reviewed some trig stuff. I'm starting to feel like it is coming back to me. Not sure I have room for anymore information. LOL

Thanks