Why is $\frac{0.5}{ \cos^2(30)} = \frac{\tan(30)}{\cos(30)} $, but $\frac{0.5}{ \cos^2(13) } \neq \frac{\tan(13)}{\cos(13)} $? Is just it a coincidence that
$$\frac{0.5}{ \cos^2(30)} = \frac{\tan(30)}{\cos(30)} $$
However
$$\frac{0.5}{ \cos^2(13) } \neq \frac{\tan(13)}{\cos(13)} $$
is not equal ? And if not does anyone know a reason why they just so happen to be equatable?

Rewrite the right side:
$$
\begin{align}
\frac{0.5}{\cos^2(30^\circ)}&=\frac{\tan(30^\circ)}{\cos(30^\circ)}\\
&=\frac{\sin(30^\circ)}{\cos^2(30^\circ)}\\
&=\frac{0.5}{\cos^2(30^\circ)}
\end{align}
$$
