proof left as an exercise

[Thomas Klemm]

Just stumbled upon this and thought some of you might enjoy solving this as well.

Quote:Prove that the following expression can be expressed as being identical to a single standard trigonometric function of an integer input with all inputs being in degrees.
You may use a calculator or trig table as a guide, but the results from the calculator or trig table will not be accepted as part of the proof.

\(
\begin{align}
\frac{2\cos(30^{\circ})}{1+4\sin(70^{\circ})} = \,?
\end{align}
\)