_____________ / ___ ___ \/ 2*a - \/ a - 8*\/ a
sqrt(2*a - sqrt(a)) - 8*sqrt(a) при a = -1/2
sqrt(2*a - sqrt(a)) - 8*sqrt(a)
sqrt(2*(-1/2) - sqrt((-1/2))) - 8*sqrt((-1/2))
sqrt(2*(-1)/2 - sqrt(-1/2)) - 8*sqrt(-1/2)
sqrt(-1 - i*sqrt(2)/2) - 4*i*sqrt(2)
(-a^0.5 + 2.0*a)^0.5 - 8.0*a^0.5