Tenemos la indeterminación de tipo
0/0,
tal que el límite para el numerador es
$$\lim_{x \to 3^+} \cot{\left(\frac{\pi x}{6} \right)} = 0$$
y el límite para el denominador es
$$\lim_{x \to 3^+} \frac{1}{\log{\left(3 - x \right)}} = 0$$
Vamos a probar las derivadas del numerador y denominador hasta eliminar la indeterminación.
$$\lim_{x \to 3^+}\left(\log{\left(3 - x \right)} \cot{\left(\frac{\pi x}{6} \right)}\right)$$
=
Introducimos una pequeña modificación de la función bajo el signo del límite
$$\lim_{x \to 3^+}\left(\log{\left(3 - x \right)} \cot{\left(\frac{\pi x}{6} \right)}\right)$$
=
$$\lim_{x \to 3^+}\left(\frac{\frac{d}{d x} \cot{\left(\frac{\pi x}{6} \right)}}{\frac{d}{d x} \frac{1}{\log{\left(3 - x \right)}}}\right)$$
=
$$\lim_{x \to 3^+}\left(\frac{\pi \left(3 - x\right) \left(- \cot^{2}{\left(\frac{\pi x}{6} \right)} - 1\right) \log{\left(3 - x \right)}^{2}}{6}\right)$$
=
$$\lim_{x \to 3^+}\left(- \frac{\pi \left(3 - x\right) \left(- \frac{\cot^{2}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{1}{6}\right) \log{\left(3 - x \right)}^{2}}{- \cot^{2}{\left(\frac{\pi x}{6} \right)} - 1}\right)$$
=
$$\lim_{x \to 3^+}\left(\frac{\frac{d}{d x} \left(- \pi \left(3 - x\right) \left(- \frac{\cot^{2}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{1}{6}\right) \log{\left(3 - x \right)}^{2}\right)}{\frac{d}{d x} \left(- \cot^{2}{\left(\frac{\pi x}{6} \right)} - 1\right)}\right)$$
=
$$\lim_{x \to 3^+}\left(- \frac{3 \left(\frac{\pi^{2} \left(3 - x\right) \left(- \cot^{2}{\left(\frac{\pi x}{6} \right)} - 1\right) \log{\left(3 - x \right)}^{2} \cot{\left(\frac{\pi x}{6} \right)}}{18} + \pi \left(- \frac{\cot^{2}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{1}{6}\right) \log{\left(3 - x \right)}^{2} + 2 \pi \left(- \frac{\cot^{2}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{1}{6}\right) \log{\left(3 - x \right)}\right)}{\pi \left(- \cot^{2}{\left(\frac{\pi x}{6} \right)} - 1\right) \cot{\left(\frac{\pi x}{6} \right)}}\right)$$
=
$$\lim_{x \to 3^+}\left(\frac{3 \left(\frac{\pi^{2} x \log{\left(3 - x \right)}^{2} \cot^{3}{\left(\frac{\pi x}{6} \right)}}{18} + \frac{\pi^{2} x \log{\left(3 - x \right)}^{2} \cot{\left(\frac{\pi x}{6} \right)}}{18} - \frac{\pi^{2} \log{\left(3 - x \right)}^{2} \cot^{3}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{\pi \log{\left(3 - x \right)}^{2} \cot^{2}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{\pi^{2} \log{\left(3 - x \right)}^{2} \cot{\left(\frac{\pi x}{6} \right)}}{6} - \frac{\pi \log{\left(3 - x \right)}^{2}}{6} - \frac{\pi \log{\left(3 - x \right)} \cot^{2}{\left(\frac{\pi x}{6} \right)}}{3} - \frac{\pi \log{\left(3 - x \right)}}{3}\right)}{\pi \cot{\left(\frac{\pi x}{6} \right)}}\right)$$
=
$$\lim_{x \to 3^+}\left(\frac{3 \left(\frac{\pi^{2} x \log{\left(3 - x \right)}^{2} \cot^{3}{\left(\frac{\pi x}{6} \right)}}{18} + \frac{\pi^{2} x \log{\left(3 - x \right)}^{2} \cot{\left(\frac{\pi x}{6} \right)}}{18} - \frac{\pi^{2} \log{\left(3 - x \right)}^{2} \cot^{3}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{\pi \log{\left(3 - x \right)}^{2} \cot^{2}{\left(\frac{\pi x}{6} \right)}}{6} - \frac{\pi^{2} \log{\left(3 - x \right)}^{2} \cot{\left(\frac{\pi x}{6} \right)}}{6} - \frac{\pi \log{\left(3 - x \right)}^{2}}{6} - \frac{\pi \log{\left(3 - x \right)} \cot^{2}{\left(\frac{\pi x}{6} \right)}}{3} - \frac{\pi \log{\left(3 - x \right)}}{3}\right)}{\pi \cot{\left(\frac{\pi x}{6} \right)}}\right)$$
=
$$0$$
Como puedes ver, hemos aplicado el método de l'Hopital (utilizando la derivada del numerador y denominador) 2 vez (veces)