1. The problem statement, all variables and given/known data By considering different paths of approach, show that the function below has no limit as (x,y) ---> (0,0). f(x,y) = - x / sqrt(x^2 + y^2). 2. Relevant equations This is the problem! I do not know the different techniques to find the limits of functions of more than one variable. My book only shows examples of cases where you can get the answer by substituting y=mx or y=kx^2. 3. The attempt at a solution I tried the above substitutions but they don't work.