Chapter 1: Sets – Exercise 1.1

Sets – Exercise 1.1 – Q.1

Each set is a collection, but each collection need not be a set, For example, a collection of beautiful women in Delhi is just a collection and not a set, for the term beautiful is not well defined. Only well defined collection of objects forms a set.

Sets – Exercise 1.1 – Q.2

(i) The collection of all natural numbers less than 50 forms a set as it is well defined.

(ii) It is not a set as the term 'good' is not well defined.

(iii) It forms a set as it is well defined.

(iv) It is not a set as the term 'most' is not well defined. A writer may be talented in the eye of one person, but he may not be talented in the eye of some other person.

(v) It is not a set as the term 'difficult' is not well defined. A topic may be difficult for one person but may not be difficult for another person, so the term 'difficult' is vague.

(vi) It forms a set as it is well defined.

(vii) It forms a set as it is well defined.

(viii) It forms a set as it is well defined.

(ix) It is not a set as the term 'most dangerous' is not well defined. The notion of dangerous animals differs from person to person.

(x) It forms a set as it is well defined