FFXI <> FFXIVFollow

For all those who are worried, I'm working on a mathematical proof to show that FFXI is, in fact, not the same as what FFXIV will be.

Ahem:

Prove FFXI <> (Not equal to) FFXIV

First, multiply both sides by FFXI:

FFXI * FFXI = FFXIV * FFXI

FFXI^2 = FFXIV*FFXI

Now, take the squareroot of both sides:

SQRT(FFXI^2)=SQRT(FFXIV*FFXI)

FFXI = SQRT(FFXIV*FFXI)

Now for some more math:

FFXI = SQRT(FF*FF*XIV*XI)

Let XIV = 14
Let XI = 11

FF11 = FF * SQRT(14*11)

FF11 = FF12.41

Floor both sides:

FLOOR(FF11) = FLOOR(FF12.41)

Therefore:
FF11=FF12
FFXI <> FFXIV

I have a similar proof that involves W0W.

I give it 24 hours before you get Guru.

Edited, Jul 1st 2009 3:17pm by Karelyn

Well, I just rated you up to scholar!

I assume it just couldn't fit in the margin of your post, right?

Yes but I think Vawn did some other math in the XI forums proving that at least some things will be exactly the same. Now where was that post....

Different context, different syntax.

I personally like =/=

But but but.....

You stated that...

FFXI * FFXI = FFXIV * FFXI

That basically just proved that FFXI = FFXIV!

Unless you are trying to prove that FF11 = FF12.41 = FF14....

Sorry...couldn't resist >.>

I know this is a joke thread, but it bugs me when my students do this, so I feel compelled to correct you. D:

"Set them equal and see if it holds true" doesn't prove anything. In order for the process to work, you need to start with an equation that is known to be true; as long as you do the same thing to both sides of the equation, you know that whatever you get at the end is also true. For instance, the following "proof" does not demonstrate that -1 = 1:

    -1 = 1 
(-1)^2 = 1^2 (square both sides) 
     1 = 1   (oh look, it's true!)

Starting with a false statement doesn't tell you anything (it doesn't even imply that your final result is false!).

Sadly I've seen graduate students in math make this same mistake....

Well, I'm not trying to step on anyone's toes here...but I'm not sure what this has to do with your original proof. =x


And being nitpicky, you didn't do the same thing to both sides there. =< You took the square of the right side, but took the negative of the square of the left. (If you're squaring -X you have to square the whole thing, not just the X part.)

I suspect I'm pushing into obnoxious territory now, so I'll shut up. =x

Well in that case... >=D


Unfortunately that is not true. =( For an example of why it isn't, see my -1 = 1 "proof" above.

The fundamental logic at work here is that if we know X and Y are the same, then for any function f, f(X) and f(Y) must also be the same (that is, X=Y implies f(X)=f(Y)). However the converse is only true for one-to-one functions, those which never "repeat" any value in their range. Taking f(x) = x^2, for example, f(X)=f(Y) does not imply that X=Y; if X and Y are negatives, their squares are still the same.


The only reason there are "special rules" is that x^2 is not one-to-one, and hence it has no inverse function. We use square roots to "undo" squaring, but without additional information it is not possible to tell whether the positive or the negative result is correct. It gets worse with periodic functions -- if sin(x) = 0, there are infinitely many possible values of x, namely all the integer multiples of pi.

My example shows that there is at least one case in which starting with a false statement nevertheless results in something true. Ergo, one cannot assume in general that starting with a statement that may or may not be true will result in a statement reflective of the original's truth value. =3

Anyway, I'm not a big fan of trying to applying rigorous logic to things that are obviously jokes, and I did laugh out loud at your original post. :) I would've kept my mouth shut except that, being a professional mathematician, I was incited to blind rage by your later comment. :P

Ohh, I see what you mean. Yes, if it is known that X <> Y and F = Y, it's of course obvious that X <> F. However, that is not the same thing as your FFXI / FFXIV proof -- in the latter you started with an equation and transformed both sides repeatedly. In that process you have only proved your result is true if the original equation is.

Semantically, in the FFXI[V] proof you started by assuming something that you know isn't true. In the F, X, Y proof you assumed something that is true; it just happened to be an inequality instead of equality. (If you had started off saying "given X <> Y and F = Y: assume X = Y..." you would be in a similar situation to the FFXI[V] proof.)

Edit:

Perhaps I just didn't read you clearly, but the process you appear to be describing here is a proof by contrapositive. That is, if you want to prove that X implies Y, it suffices to show that (not Y) implies (not X). If that's what you meant, it was not obvious to me from your exposition. =<

Edited, Jul 2nd 2009 4:53pm by analysis

This topic makes me wanna kill myself with my stupidity.




I lol'd