Recent content by Fumbles22

Hello, I'm stuck on this question, and it's really annoying me. I scanned the page so it has a bit more context. It's question 3.7: "A long wire carrying a steady current is placed in a uniform magnetic field parallel to it's own length. What is the shape of the magnetic field lines...

I think I get it. The Existential Hypothesis rule is quite hard compared to the others. When I was reading the page, I accidentally read "elimination" as "eradication". Since I was in learning mode, I remembered it as eradication. When I was writing the post I was thinking "it's...

Why is it that v occurs freely in ? We know that v is bound in \(\psi\), so how do we know it's free here? \(\neg\phi\leftrightarrow\psi\)

This question is really getting on my nerves. It's 6i) from here: Right off the bat, it looks like they've thrown me a curveball. The fact that v does not occur free in \psi means that the Existential Hypothesis rule is going to need some care when applied. I've come up with two possible...

I managed to do it. Oddly enough, I used the method that the book! For some reason. I couldn't get it to work yesterday. Today it worked like a charm. Thanks for your help Makarov.

I'm afraid I'm just starting out, so I think some of this information has been removed from my notes in the name of simplicity. This isn't necessarily a bad thing, too much information at the start of a module would be downright confusing. Although the question does not state it, I think x...

Give a formal proof to show \forall x (0' + x' ) = (x . 0'') \vdash \exists x (x + x')= (x . x') I'm new to these, and this one looks like it should be easy. What I want to do is: 1). substitute x into where there are already x's. 2). Make the statement valid for all y 3). substitute y into...