We can start ourinvestigationin the following way:

(i) If we choose , you'll easily find that satisfies the given hypothesis. In this case, we have .

(ii) If we choose

then, and also satisfies the given conditions. In this case, .

Taking into account these results my questions are:

(a) Have you quoted the exact formulation of the problem ?.

(b) Are there additional hypothesis for and ?

(c) In what terms we have to find those limits ?