First, don't forget that:
Why would you "drop" the variables? You have (4x²) / (1x²+5m²x²) = (4x²) / [(1+5m²)x²] = 4/(1 + 5m²)
ƒ(x,y) = (4x²) / (1x²+5y²)
What is the limit along the line y=mx
The function then becomes...
ƒ(x,mx) = (4x²) / (1x²+5mx²)
I thought the answer was then as easy as dropping all the variables and seeing that approaching the origin the function is closest to 4/6, but this is incorrect.
What am I not understanding?