= Sqrt(b^3/a)*Sqrt(a^2/b^6)
= Sqrt((b^3*a^2)/(a*b^6))
= Sqrt(a/b^3)
= Sqrt(a/b^3) 或 = Sqrt(a/b)/b
即根号下b的3次方分之a 或 b分之根号下b分之a