It is easy to verify that...
... so that has as domain the whole x-y plane and it is continous everywhere...
a) Find the domain of f.
b) How can it be defined at all points not in its domain so the resulting
function is continuous everywhere in the xy-plane?
a) its domain is the whole xy plane expept for the line y=-2x.
b) I really have no clue how to approach this. Can somebody help??