
Patrick B. answered 09/27/20
Math and computer tutor/teacher
You are allowed to use the contrapositive.
So then, when Translating to english,
You can use IF and ONLY IF, and simplify/summarize
the statements.
Given premesis:
THe arguments are not in order
I grumble if and only if I do not understand,
which is equivalent to : I do not grumble iff I understand
Example is not easy if and only if I have headache
which is equivalent to: I do not have headache iff it is easy
If they are not in order then I do not understand
I grumble if it gives me a headache
The PROOF is:
The arguments are not in order
--> I do not understand
--> I grumble
--> I have headache
--> not easy