Give an Appropriate Answer $f ( x , y )$ And the Positive Number

Essay

Give an appropriate answer.
-Given the function $f ( x , y )$ and the positive number $\varepsilon$ as in the formal definition of a limit, find a positive number $\delta$ as in the definition that insures $| \mathrm { f } ( \mathrm { x } , \mathrm { y } ) - \mathrm { f } ( 0,0 ) | < \varepsilon$ .
$f ( x , y ) = \frac { x + y } { x ^ { 2 } + y ^ { 2 } + 1 } ; \varepsilon = 0.06$