a) Let E1 denote the closed ball centered at (0, 0) of radius 1 and E2 := 2(2, 0), and sketch a graph of the

a) Let E1 denote the closed ball centered at (0, 0) of radius 1 and E2 := β√2(2, 0), and sketch a graph of the set
U: = {(x, y): x2 + y2 < 1 and x2 - 4x + y2 + 2 < 0}.
b) Decide whether U is relatively open or relatively closed in E1. Explain your answer.
c) Decide whether U is relatively open or relatively closed in E1. Explain your answer.