State which of the following sets are singleton sets.
(i) A={x|x=16}
(ii) B={y|y2=36}
(iii) C={p|p∈I,p3=−8}
(iv) D={q|(q−4)2=0}
(v) E={x|1+2x=3x,x∈W}
Singleton set: A set that contains a single element is called a singleton set.
(i) A={x|x=16}
Roster form of set A={16}
This set consists of only one element. Therefore, it is a singleton set.
(ii) B={y|y2=36}
Since, y2=36
⇒y=±6
Roster form of set B={+6, −6}
This set consists of two elements. Therefore, it is not a singleton set.
(iii) C={p|p∈I,p3=−8}
Since, p3=−8
⇒p3=(−2)3
⇒p=−2
Roster form of set C={−2}
This set consists of only one element. Therefore, it is a singleton set.
(iv) D={q|(q−4)2=0}
Since, (q−4)2=0
⇒q−4=0
⇒q=4
Roster form of set D={4}
This set consists of only one element. Therefore, it is a singleton set.
(v) E={x|1+2x=3x,x∈W}
Since, 1+2x=3x,x∈W
⇒2x−3x=−1
⇒−x=−1
⇒x=1
Roster form of set E={1}
This set consists of only one element. Therefore, it is a singleton set.