Trig Help: Deriving a Friction Equation from Circular Motion Example

[CINA]

Homework Statement

Well I'm following an example problem on this site:
http://www.batesville.k12.in.us/physics/PhyNet/Mechanics/Circular Motion/banked_with_friction.htm
I just need some help on the derivation math. I'll just host the image below.

Homework Equations

This is the problem equation:
http://img105.imageshack.us/img105/3449/frictioneqn4.th.gif

On the last line when it goes from sines and cosines to tangants I can't follow what the person did.

The Attempt at a Solution

I'm assuming he used some type of trig Identity but I can't find one that is apt. I thinking it's a sum/difference trig identity but it just doesn't help. What could he be doing?

Any help at all is GREATLY apperciated!

Thanks

 

[LowlyPion]

Multiply top and bottom by 1/cosθ