Hey New here on the forum. I have a small problem with some contrapositive proofs..
I have to make a contrapositive proof that:
∀x, y ∈ R : x · y < 1 ⇒ x < 1 ∨ y < 1
I can logically see what I'm supposed to do.. and that the statement is correct.. but how do i prove it?? I know that the normal way is to prove that http://upload.wikimedia.org/math/7/2...53a3799b9a.png .. but I'm a little stuck from there.. anyone here who can help?