Tenemos la indeterminación de tipo
0/0,
tal que el límite para el numerador es
$$\lim_{x \to 0^+} \operatorname{asin}{\left(2 x \right)} = 0$$
y el límite para el denominador es
$$\lim_{x \to 0^+} \frac{1}{\cot{\left(3 x \right)}} = 0$$
Vamos a probar las derivadas del numerador y denominador hasta eliminar la indeterminación.
$$\lim_{x \to 0^+}\left(\cot{\left(3 x \right)} \operatorname{asin}{\left(2 x \right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \operatorname{asin}{\left(2 x \right)}}{\frac{d}{d x} \frac{1}{\cot{\left(3 x \right)}}}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{2 \cot^{2}{\left(3 x \right)}}{\sqrt{1 - 4 x^{2}} \left(3 \cot^{2}{\left(3 x \right)} + 3\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{2 \cot^{2}{\left(3 x \right)}}{3 \cot^{2}{\left(3 x \right)} + 3}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \frac{1}{3 \cot^{2}{\left(3 x \right)} + 3}}{\frac{d}{d x} \frac{1}{2 \cot^{2}{\left(3 x \right)}}}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{1}{\left(6 \cot^{2}{\left(3 x \right)} + 6\right) \left(- \frac{9 \cot^{4}{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}} - \frac{18 \cot^{2}{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}} - \frac{9}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \frac{1}{6 \cot^{2}{\left(3 x \right)} + 6}}{\frac{d}{d x} \left(- \frac{9 \cot^{4}{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}} - \frac{18 \cot^{2}{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}} - \frac{9}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{6 \left(- 6 \cot^{2}{\left(3 x \right)} - 6\right) \cot{\left(3 x \right)}}{\left(6 \cot^{2}{\left(3 x \right)} + 6\right)^{2} \left(- \frac{9 \left(36 \left(- 18 \cot^{2}{\left(3 x \right)} - 18\right) \cot^{5}{\left(3 x \right)} + 36 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}\right) \cot^{4}{\left(3 x \right)}}{\left(- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}\right)^{2}} - \frac{18 \left(36 \left(- 18 \cot^{2}{\left(3 x \right)} - 18\right) \cot^{5}{\left(3 x \right)} + 36 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}\right) \cot^{2}{\left(3 x \right)}}{\left(- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}\right)^{2}} - \frac{9 \left(36 \left(- 18 \cot^{2}{\left(3 x \right)} - 18\right) \cot^{5}{\left(3 x \right)} + 36 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}\right)}{\left(- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}\right)^{2}} - \frac{9 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}} - \frac{18 \left(- 6 \cot^{2}{\left(3 x \right)} - 6\right) \cot{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{6 \left(- 6 \cot^{2}{\left(3 x \right)} - 6\right) \cot{\left(3 x \right)}}{\left(6 \cot^{2}{\left(3 x \right)} + 6\right)^{2} \left(- \frac{9 \left(36 \left(- 18 \cot^{2}{\left(3 x \right)} - 18\right) \cot^{5}{\left(3 x \right)} + 36 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}\right) \cot^{4}{\left(3 x \right)}}{\left(- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}\right)^{2}} - \frac{18 \left(36 \left(- 18 \cot^{2}{\left(3 x \right)} - 18\right) \cot^{5}{\left(3 x \right)} + 36 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}\right) \cot^{2}{\left(3 x \right)}}{\left(- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}\right)^{2}} - \frac{9 \left(36 \left(- 18 \cot^{2}{\left(3 x \right)} - 18\right) \cot^{5}{\left(3 x \right)} + 36 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}\right)}{\left(- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}\right)^{2}} - \frac{9 \left(- 12 \cot^{2}{\left(3 x \right)} - 12\right) \cot^{3}{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}} - \frac{18 \left(- 6 \cot^{2}{\left(3 x \right)} - 6\right) \cot{\left(3 x \right)}}{- 36 \cot^{6}{\left(3 x \right)} - 36 \cot^{4}{\left(3 x \right)}}\right)}\right)$$
=
$$\frac{2}{3}$$
Como puedes ver, hemos aplicado el método de l'Hopital (utilizando la derivada del numerador y denominador) 3 vez (veces)