Consider the curves, $x^2+y^2 =1$ and $(x-1)^2 +y^2=1.$ Area enclosed by the two curves is :

$\left(\frac{\pi }{3}-\sqrt{3}\right) sq.units $ $\left(\frac{2\pi }{3}-\frac{\sqrt{3}}{2}\right) sq.units $ $\left(\frac{2\pi }{3}+\frac{\sqrt{3}}{2}\right) sq.units $ $\left(\frac{\pi }{3}+\sqrt{3}\right) sq.units $

$\left(\frac{2\pi }{3}-\frac{\sqrt{3}}{2}\right) sq.units $