$$0.512(2)(2)(( \frac{ \sqrt{ 0.75 } }{ 1+ \sqrt{ 0.75 } } -0.2(0.75)$$
$\frac{512\sqrt{3}}{125}-6.4512\approx 0.643280108$
$\frac{512 \sqrt{3} - 806.4}{125} = 0.6432801078021212$
