Yes. It has 2 ranges. This only fulfills the "always positive and negative" condition only. Your function is either always positive or negative or even both. The question seeks for the "always positive" condition. In order to fulfill the condition fully, you need to reject the negative sqrt 3 range. This is because your x^2 coefficient is negative when you sub any values for that range. Meaning, your function is always negative. You don't have to reject only if the question states "always positive or always negative or both". I hope that answers your qn.