What universal set(s) would you propose for each of the following?
(i) The set of right triangles, (ii) The set of isosceles triangles.
(i)  All right triangles are also triangles. Each member of set containing right angled triangles is a member of the set containing a triangles.
   U  = { c : c is a triangl;e in a plane}
(ii)   All isosceles triangles are also triangles. Each member of set containing isosceles triangles is a member of the set containing a triangles.
  U = { x: x is a triangle in a plane}
Write down all the subsets of the following sets
(i) {a} (ii) {a, b} (iii) {1, 2, 3} (iv) φ
Given sets A = {1, 3, 5}, B = {2, 4, 6}, C = {0, 2, 4, 6, 8}, which of the following can be considered as universal set(s) of three sets A, B, C ?
(i) {0,1,2,3,4,5,6}Â (iii)Ï•
(iii) {0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10}Â (iv) {1, 2, 3, 4, 5, 6, 7, 8}
Write the following as intervals :
(i) {x : x ∈ R, – 4 < x ≤ 6} (ii) {x : x ∈ R, – 12 < x < –10} (iii) {x : x ∈ R, 0 ≤ x < 7} (iv) {x : x ∈ R, 3 ≤ x ≤ 4}
Write the following intervals in set-builder form :
(i)-∞ 31 (ii) (-∞, 0) (iii) [-1, ∞) (iv) (3, ∞)