(x-0.50)2=y, x=0.50±√y,
(y-0.50)2=z, y=0.50±√z,
(z-0.50)2=0, so z=0.50, therefore:
(y-0.50)2=0.50, y=0.50±√0.50, and:
x=0.50±√(0.50±√0.50).
√0.5=0.7071 approx. y=1.2071 or -0.2071. We can reject the negative result because there's no real root of a negative number.
x=0.50±√y=0.50±√1.2071=1.5987 or -0.5987.