For the following set, state with reasons whether it is a null set.
$B = {b | b \in N, 2 b + 1$ is even $}$

Question

Q. For each of the following sets. state with reasons whether it is a null set.
(i) A = {x|x

\in

I x² is not positive}
(ii) B = {b|b

\in

N, 2b + 1 is even}
(iii) C = {c|c

\in

N, c is odd and c² is even}

Answer 1

Set B is a null set because for every natural number

b, (2 b + 1)

is an odd number.

Answer 2

Let's take one example,

Answer 3

After putting

b = 3

in

2 b + 1

we get

2 (3) + 1 = 7

,which is a odd number.

Answer 4

Let's take another example, after putting

Answer 5

Hence,

B

is a null set

For the following set, state with reasons whether it is a null set.B={b|b∈N,2b+1 is even}