Email
Chat with tutor
logo

Ask Questions, Get Answers

X
 
Questions  >>  CBSE XII  >>  Math  >>  Relations and Functions
Answer
Comment
Share
Q)

The identity element for the binary operation $\ast$ defined on $Q\sim \{0\}$ as $a\ast b=\large{\frac{ab}{2}} \normalsize \;a,b\in Q\sim\{0\}$ is

(A) 1 (B) 0 (C) 2 (D) none of these

1 Answer

Comment
A)
Toolbox:
  • 'e' is the identity element for binary operation * on Q-{0} if
  • $ a *e=e *a=a$
$ a* b=\frac{ab}{2} \qquad a,b \in Q-\{0\}$
 
$ a* b=a => \frac{ab}{2}=a$
 
$=> b=2$
 
$a*2=\frac{a.2}{2}=a$
 
$2*a=\frac{2.a}{2}=a$
 
e=2 is the identity element for * operation
 
'c' option is correct
Help Clay6 to be free
Clay6 needs your help to survive. We have roughly 7 lakh students visiting us monthly. We want to keep our services free and improve with prompt help and advanced solutions by adding more teachers and infrastructure.

A small donation from you will help us reach that goal faster. Talk to your parents, teachers and school and spread the word about clay6. You can pay online or send a cheque.

Thanks for your support.
Continue
Please choose your payment mode to continue
Home Ask Homework Questions
Your payment for is successful.
Continue
Clay6 tutors use Telegram* chat app to help students with their questions and doubts.
Do you have the Telegram chat app installed?
Already installed Install now
*Telegram is a chat app like WhatsApp / Facebook Messenger / Skype.
...