x = \(\sqrt{1-t^2},y=sin^{-1}(t)
\)
\(\frac{dx}{dt}=\frac1{2\sqrt{1-t^2}}\times-2t\) and \(\frac{dy}{dt} = \frac1{\sqrt{1-t^2}}\)
\(\frac{dy}{dx}=\cfrac{\frac{dy}{dt}}{\frac{dx}{dt}}\) = \(\cfrac{\frac{1}{1-t^2}}{\frac{-t}{\sqrt{1-t^2}}}\) = \(-\frac1t\)