Help finding phase angle

[davidd31415]

I'd appreciate some help with this equation... I've been looking at it
for a few days now...

Here's the equation:

http://img367.imageshack.us/img367/1222/...

I'm trying to understand how the formula for the phase angle is
determined.


Thanks for any help.

 

[davidd31415]

Link doesn't work for me.

Chris

My mistake. Correct link:

http://img367.imageshack.us/img367/1222/img7229xj0.jpg