1. The problem statement, all variables and given/known data https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/10923273_407123639463753_2874228726948727052_n.jpg?oh=27c882da16071e65bbb420147333ec38&oe=558413E4&__gda__=1434978872_d03c8531060688181560956b68c96650 Is f continuous at (0,0)? What is the "maximum" region D where f is continuous? 2. Relevant equations 3. The attempt at a solution I think, by the graph, that in (0.0) the function is not continuous. However I can't realize what curves to choose for show the discontinuity. I actually started around curves such that https://scontent-mia.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/10986437_407156659460451_678008542589932086_n.jpg?oh=7655e3989f7fcce725524cbfb67cdd60&oe=55585B76 but it was useless. Thanks in advance. Sorry for my English.