Express, in simplest form, the value of
\[\sqrt{\frac{3}{4} - \sqrt{\frac{1}{2}}} - \sqrt{\frac{3}{4} + \sqrt{\frac{1}{2}}}.\]
from sympy import sqrt, simplify

expr = sqrt(3/4 - sqrt(1/2)) - sqrt( 3/4 + sqrt(1/2) )

value = simplify(expr)

print(value)