0 votes 0 votes https://youtu.be/b0XINQEQPWE in this video,Kiran Kumar Sir at 36:30 says the two formulas are not valid. But in 2016 gate question,option C https://gateoverflow.in/39618 says its valid. please confirm: Mathematical Logic usergate2016 usermod kirankumarsir + – Mr L asked Dec 2, 2018 Mr L 594 views answer comment Share Follow See 1 comment See all 1 1 comment reply kumar.dilip commented Dec 2, 2018 reply Follow Share Definitely, C is valid. you can take domain to verify that. 1 votes 1 votes Please log in or register to add a comment.