Question

A={x:-5<x <O, x £N} find the
Cordinal number of set A.?​

Answer 1

Answer:

n(A) = 0

Note:

★ Null set : The set which doesn't contain any element is called null set .

★ Null set is also known as empty set or void set.

★ Cardinal number : The number of elements in a set is called its cardinal number. Cardinal number of a set A is denoted by n(A) .

★ The cardinal number of a null set is zero.

Solution:

Here , we have ;

A = { x : -5 < x < 0 , x € N }

It is clear that , there is no natural number which lies between -5 and 0 .

Thus,

There is no element in the given set A.

Thus,

Set A is an empty set , ie ; A = ∅

Hence,

The cardinal number of set A is zero,

ie ; n(A) = 0