Cardinal numbers

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Set Theory › Cardinal numbers

Questions 1 - 2

1

Given the set , calculate the cardinality.

$A=\begin{Bmatrix} a,a,b,c,d,e,e \end{Bmatrix}$

$|A|=\frac{a+e}{7}$

Explanation

Given a set , the cardinality is the number of elements in . This is also written as .

Looking at this particular problem,

$A=\begin{Bmatrix} a,a,b,c,d,e,e \end{Bmatrix}$

First, rewrite the set to depict a more accurate description of the space.

$A=\begin{Bmatrix} a,b,c,d,e \end{Bmatrix}$

Therefore, counting up the number of elements, results in the following cardinality,

2

Given the set , calculate the cardinality.

$A=\begin{Bmatrix} 3,7,5,4,9,11,24 \end{Bmatrix}$

Explanation

Given a set , the cardinality is the number of elements in . This is also written as .

Looking at this particular problem,

$A=\begin{Bmatrix} 3,7,5,4,9,11,24 \end{Bmatrix}$

Therefore the number of elements in a is,

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