I am trying to prove the limit of the function (2x^2 + y^2) / (x^2 + y^2) as (x,y) ---> (-1 , 2) is 6/5. So I have 0 < sq((x+1)^2 + (y-2)^2) < delta and f(x) - 6/5 < Epsilon I found a common denominator and made epsilon the quotient of two polynomials. Also, i recognized that you could factor the numerator to yield some function of delta. However, the denominator is becoming a problem. I get that the numerator is less than 4D^2 + 8D + D^2 + 4D, after using the triangle inequality, but i don't know what to do with the denominator. Am i close to the right method, or am i totally doing it wrong? Is proving this even possible?