Question

Let sets A and B be defined as follows:

A= {j, k, l, m, q, r}
B is the set of integers greater than -2 and less than 2

(a) Find the cardinalities of A and B.
n(A) =
n(B)=

(b) Select true or false.
(I've attached a picture below to help other)

Answer 1

Explanation:

(a)

it just means how many members are in a set.

there is no mystery or strange mathematical approach. we simply need to count them.

when there is an interval given, sure, we can calculate the length. but for a short interval counting is still faster.

n(A) = 6

n(B) = 3 {-1, 0, 1}

the calculation would be 2 - -2 - 1 = 4 - 1 = 3.

the "-1" comes from the fact that the end of the interval is not included.

(b)

z is not in A. as we can see : true

l is in A. as we can see again : yes. true.

-1 is in B. as I listed above : yes, true.

7 is in B. no, definitely not. false.