Chapter 2 - Set Theory - 2.3 Venn Diagrams and Set Operations - Exercise Set 2.3 - Page 81: 34

C ∪∅ = { 2,3,4,5,6}

C∪∅ U = {1,2,3,4,5,6,7} C = {2,3,4,5,6} The set C ∪∅ represents all elements of C and elements of ∅ (∅ represent empty set). Therefore the elements of C∪∅ are 'C' elements only i.e. 2,3,4,5,6 C ∪∅ = { 2,3,4,5,6}.