Daily Drills 21 - Section 21 - Question 5

If the tyrannosaur is not included in the display, then the display must contain each of the following EXCEPT:

LadyMae January 9, 2019

“Logical opposite”

How can the logical opposite of must be true be not necessarily true? I am really struggling to remember these logical opposites because it sounds like the opposite of must be true would be must not be true which is cannot be true.

Replies
Create a free account to read and take part in forum discussions.

Already have an account? log in

Ravi January 9, 2019

@LadyMae,

Great question! It looks like the problem you're having is where
you're putting the "not" in the logically opposite statement.

The logical opposite of "must be true" is "not must be true," which
means the same thing as "not necessarily true."

"Not must be true" just means that it doesn't have to be true. This
has a far different meaning than "must not be true," which is the
equivalent of saying "must be false."

When doing logical opposites, make sure that you put "not" before the
entire statement, not in between words within the statement.

Does this make sense? Let us know if you have any other questions!

LadyMae January 10, 2019

Yeah that makes sense! Thanks!