Kenneth Rosen Edition 6th Exercise 1.2 Example 1 (Page No. 17)

Question

"You can access the Internet from campus only if you are a computer science major or you are not a freshman"

According to Rosen, its equivalent compound proposition is a $→ (c ∨¬f )$.

Should it not be the other way round?  $(c ∨¬f ) →  a$

Comments

@Warlock Consider this statement

She'll marry you only if you are rich.

Now, if she marries you it does mean that you are rich. But if you are rich it does not mean that she'll marry you -- there are other rich people too.

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Yes @Arjun I get it now :)

This is a great link : http://qr.ae/TUTlbc

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https://gateoverflow.in/42915/kenneth-rosen-edition7-ch-1-ex-1-2-queno-2

Answer 1

Note that in logic the phrase "only if" is equal to "if....then"

Here the statement is 

"You can access the Internet from campus only if you are a computer science major or you are not a freshman"

The above statement is equal to

"If you can access the Internet from campus then you are a computer science major or you are not a freshman"

So, the correct answer is a → (c ∨¬f )

Comments

It is correct, but how is it different in plain English - only if always mean that only rt?

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Yes sir,

In English the meaning of "only if" should be same as logic.

I had the wrong concept thanks for pointing that out.

Answer 2

Given in Rosen itself :)

P: you can access the internet from campus

Q: you are a computer science major or you are not a freshman