Question

If A is any set prove that A is subset of null set then A is equal to null set

Answer 1

Answer:

If A belongs to a null set, how can I prove that A=null set?

A is a member of the null set. (Given)

The null set has no members (By definition)

A is not a member of the null set. (Universal instantiation from (2))

A is a member of the null set, or A is the null set (Disjunction Introduction from 1)

A is the null set (Disjunctive Syllogism, from 3, 4)

Step-by-step explanation:

If A belongs to a null set, how can I prove that A=null set?

A is a member of the null set. (Given)

The null set has no members (By definition)

A is not a member of the null set. (Universal instantiation from (2))

A is a member of the null set, or A is the null set (Disjunction Introduction from 1)

A is the null set (Disjunctive Syllogism, from 3, 4)