The square root of negative numbers do not exist in the real field of numbers. A radical expression (square root) function will be defined ONLY for those values of the variable that will render the expression under the root sign positive. To get the domain of a square root function therefore will require that we solve the inequality in which the expression under the square root sign is less than zero. This will give us the set of values that will make the expression NEGATIVE thus making the function undefined. The required domain will therefore be the set of real numbers EXCLUDING the set of solution gotten for the inequality. @EndzeMathsSolutions-mp1wn