Поскольку функция нечетная, то f(-x) = -f(x).
f(-2) = -f(2) = -(-2² - 1/2) = -( -4 - 1/2) = 4 + 1/2 = 9/2.
f(-1/2) = -f(1/2) = -((1/2)² - 1/(1/2)) = -(1/4 - 2) = -(1/4 - 8/4) = -(-7/4) = 7/4.
f(-2) - f(-1/2) = 9/2 - 7/4 = 18/4 - 7/4 = 11/4.