How to prove $\frac{1+\sin{6^\circ}+\cos{12^\circ}}{\cos{6^\circ}+\sin{12^\circ}}=\sqrt{3}$? I found this interesting result. Show that
$$\dfrac{1+\sin{6^\circ}+\cos{12^\circ}}{\cos{6^\circ}+\sin{12^\circ}}=\sqrt{3}.$$
See this Wolfram Alpha output.
My attempt is very ugly. We know that
$$\sin{6^\circ}=\dfrac{1}{8}(-1-\sqrt{5})+\dfrac{1}{4}\sqrt{\dfrac{3}{2}(5-\sqrt{5})}$$
$$\cos{6^\circ}=\dfrac{1}{4}\sqrt{\dfrac{1}{2}(5-\sqrt{5})}+\dfrac{1}{8}\sqrt{3}(1+\sqrt{5})$$
$$\sin{12^\circ}=2\sin{6^\circ}\cos{6^\circ}$$$$\cos{12^\circ}=2\cos^2{6^\circ}-1$$ and it is very ugly, maybe there exist simple methods.
Thank you.

Here is a proof based on the cosine-sum formula $\cos(A+B)=\cos A\cos B-\sin A\sin B$. After multiplying through by the denominator, the RHS minus the LHS is $$\sqrt3\cos6^\circ-\sin6^\circ+\sqrt3\sin12^\circ-\cos12^\circ-1$$
$$=2\cos30^\circ\cos6^\circ-2\sin30^\circ\sin6^\circ-(2\cos60^\circ\cos12^\circ-2\sin60^\circ\sin12^\circ)-1$$
$$=2\cos(30^\circ+6^\circ)-2\cos(60^\circ+12^\circ)-1$$
$$=2\frac{\sqrt5+1}{4}-2\frac{\sqrt5-1}{4}-1$$
$$=0.$$
To see that $\cos36^\circ=(\sqrt5+1)/4$: Using the cosine-sum formula and the fact that $\cos^2\theta+\sin^2\theta=1$, we obtain $\cos2\theta=2\cos^2\theta-1$ and then, using also the formula $\sin2\theta=2\sin\theta\cos\theta$, we derive $\cos3\theta=4\cos^3\theta-3\cos\theta$. For our value $\theta=36^\circ$, note that $\cos3\theta=-\cos2\theta$. This reduces to a cubic equation in $\cos\theta$:$$4\cos^3\theta+2\cos^2\theta-3\cos\theta-1=0.$$We can easily spot one (irrelevant) solution $\theta=\pi$, or $\cos\theta=-1$; so, factoring out $\cos\theta+1$ leaves the quadratic $4\cos^2\theta-2\cos\theta-1=0$, with the positive root yielding $\cos36^\circ$. The value of $\cos72^\circ$ is easily obtained now from $\cos2\theta=2\cos^2\theta-1$. 
