[tex]\frac{1}{7} e^{-2t} \cos(4 \sqrt 6 t)+\frac{\sqrt 6}{21} e^{-2t} \sin(4 \sqrt 6 t) =\frac{\sqrt 15}{21} e^{-2t} \cos(4 \sqrt 6 t+\arctan \sqrt 6/2)[/tex](adsbygoogle = window.adsbygoogle || []).push({});

I am having trouble figuring out how to prove this relation. Any help would be greatly appreciated. My initial thought was to use this formula:

[tex]\cos(u+v)=\cos(u) \cos(v)+\sin(u) \sin(v)[/tex]

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

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

# Simplification of Trigonometic Expression

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