Let’s find horizontal asymptotes with help of the limits of this function at x->+oo and x->-oo
$$\lim_{x \to -\infty} \operatorname{asin}{\left(\sqrt{\sqrt{2}} - \frac{2}{\sqrt{5 x}} \right)} = \operatorname{asin}{\left(\sqrt[4]{2} \right)}$$
Let's take the limitso,
equation of the horizontal asymptote on the left:
$$y = \operatorname{asin}{\left(\sqrt[4]{2} \right)}$$
$$\lim_{x \to \infty} \operatorname{asin}{\left(\sqrt{\sqrt{2}} - \frac{2}{\sqrt{5 x}} \right)} = \operatorname{asin}{\left(\sqrt[4]{2} \right)}$$
Let's take the limitso,
equation of the horizontal asymptote on the right:
$$y = \operatorname{asin}{\left(\sqrt[4]{2} \right)}$$