Inclined asymptote can be found by calculating the limit of 1 - sin(1/2)*x, divided by x at x->+oo and x ->-oo
$$\lim_{x \to -\infty}\left(\frac{- x \sin{\left(\frac{1}{2} \right)} + 1}{x}\right) = - \sin{\left(\frac{1}{2} \right)}$$
Let's take the limitso,
inclined asymptote equation on the left:
$$y = - x \sin{\left(\frac{1}{2} \right)}$$
$$\lim_{x \to \infty}\left(\frac{- x \sin{\left(\frac{1}{2} \right)} + 1}{x}\right) = - \sin{\left(\frac{1}{2} \right)}$$
Let's take the limitso,
inclined asymptote equation on the right:
$$y = - x \sin{\left(\frac{1}{2} \right)}$$