Sketch the indicated set. Describe the boundary of the set. Finally, state whether the set is open, closed or neither.D = {(x, y) : 2 < + < 4}

Question

A.

The boundary is the square with vertices
 (-4, 0), (0, 4), (4, 0), and (0, -4). The interior
 is the set of all points in the region inside
 the boundary square. The set is open.
B.

The boundary is the square with vertices
 (-2, 0), (0, 2), (2, 0), and (0, -2). The interior
 is the set of all points inside the boundary
 square. The set is open.
C.

The boundaries are squares. The first has
 vertices (-2, 0), (0, 2), (2, 0), and (0, -2)
 and the second has vertices (-4, 0), (0, 4),
 (4, 0), and (0, -4). The set is open.
D.

The boundaries are squares. The first has
 vertices (-2, 0), (0, 2), (2, 0), and (0, -2)
 and the second has vertices (-4, 0), (0, 4),
 (4, 0), and (0, -4). The set is closed.

Answer 1

Answer: C