Question

Which of the following is not a subgroup of (R, +)
A
(2+)
B
(Q,+)
C{0}
D
(-1,0,1)​

Answer 1

Answer:

D (-1,0,1)

is not subgroup of R+

Answer 2

Answer:

Given,

Main group- (R,+).

To Find,

The subgroup of the Main-group- (R,+).

Solution,

We can simply find the subgroup, by applying the definition of R and subgroup.

Subgroup- Anything that is a part of the main group.

"R" is the collection of all the real numbers we can represent on the straight number line.

(R,+)- a collection of all the numbers, which can be represented on the number line.

Option a- contains "2", which is a positive number that can be represented on the number line.

Option b- contains "Q" which is the set of an irrational number. irrational numbers cannot be represented on the number line. Therefore, it is not a subgroup of the given set.

Option c- "0" can be represented on the number line.

Option d- all the three numbers in this set can be represented on the number line.

Hence, option b is not a subgroup of (R,+).