Question

Which of the following are empty sets ? why ?

( i ) A = { a | a is a natural number smaller than zero.}

( ii ) B = { x | x 2 = 0}
( iii ) C = { x | 5 x - 2 = 0, x$\in$N}

Answer 1

(i) A = {a | a is a natural number smaller than zero.} = {}

So, A is an empty set.

(ii) B = {x | x² = 0} = {0}

So, B is not an empty set.

(iii) C = {x | 5x $-$ 2 = 0, x$\in$N} = {}

So, C is an empty set.