Homework Statement D1 = {(x,y) : x^2 + y^2 < 3, x+2y = 2} D2={(x,y) : x^2 + y^2 > 2} D3={(x,y) : x + 2y = 2} Homework Equations The Attempt at a Solution D1 is neither, D2 is open and D3 is closed, am I right or wrong?