Let y=y(x) be a solution of the differential equation, √(1-x^2) (d y)/(d x)+√(1-y^2)=0,|x|<1. If y(1/2)=(√ 3)/2, then y(-1/(√ 2)) is equal to:

Let $\displaystyle y=y(x)$ be a solution of the differential equation, $$\sqrt{1-x^2} \frac{\mathrm{~d} y}{\mathrm{~d} x}+\sqrt{1-y^2}=0,|x|<1 . $$ If $\displaystyle y\left(\frac{1}{2}\right)=\frac{\sqrt{3}}{2}$, then $\displaystyle y\left(\frac{-1}{\sqrt{2}}\right)$ is equal to: