Hi! I have some doubts bound up with an exercise of limits. It demands to calculate the existence of the limit in (0,0) of these two functions. My solution for the first one til now is: Well, after the substitution we have So we can use Using And Well, I don't know if I've done correctly all the process, but if I did, I guess that in the next step I have to calculate the limit by the definition to conclude the exercise, and that's one of the things that I don't know how to do. The second exercise is similar to the first one but I don't know how to do it either. Maybe the minus changes the result and there's not limit and any necessity of employing the definition. Anyhow, can someone lend me a hand? :) Thanks!