Unit 11 Answers

1. a) {-2, 2}      b)

2. a) Yes        b) No        c) No

3. a) No     b) Yes     c) Yes      d) No      e) No      f) No

4. Let x be an arbitrary element of A.  We are going to show that x C.  Since A B, this implies that x B.  SinceB C, we see that x C.  Since x A implies that x C, it follows that A C.

5.

1. {, {a}}
2. {, {a}, {{a}}, {a, {a}} }
3. {, {}, {{}}, {, {}}}