Question

f(x)=2x+5xy-3y^2,using the defination of a limit,prove that lim(x,y)>(2;1)=11

Answer 1

Use this:\[
\sqrt{(x-2)^2+(y-1)^2}<\delta\implies |2x+5xy-3y^2-11|<\epsilon
\]

Answer 2

This is the definition for multi-variable functions.