Inclined asymptote can be found by calculating the limit of acos(x) - sqrt(1 - 3*x^3/10), divided by x at x->+oo and x ->-oo
$$\lim_{x \to -\infty}\left(\frac{- \sqrt{1 - \frac{3 x^{3}}{10}} + \operatorname{acos}{\left(x \right)}}{x}\right) = \infty$$
Let's take the limitso,
inclined asymptote on the left doesn’t exist
$$\lim_{x \to \infty}\left(\frac{- \sqrt{1 - \frac{3 x^{3}}{10}} + \operatorname{acos}{\left(x \right)}}{x}\right) = - \infty i$$
Let's take the limitso,
inclined asymptote on the right doesn’t exist