(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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.

2. Relevant equations

This is the problem equation:

http://img105.imageshack.us/img105/3449/frictioneqn4.th.gif [Broken]

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

3. 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

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Just a little trig help

**Physics Forums | Science Articles, Homework Help, Discussion**