a) Sketch a graph of the set
{(x,y): x2 + 2y2 0},
and decide whether this set is relatively open or relatively closed in the subspace {(x, y) : y > 0}. Do the same for the subspace {(x, y): x2 + 2y2 b) Sketch a graph of set
{(x, y): x2 + y2

i(0, 0)