Does Batman Equation really work?
And can we "union" relations?

(Sorry for long reply.)

Question

Does Batman Equation really work?
And can we "union" relations?

(Sorry for long reply.)

geerky42 · Answer

I just happened to discover this question in Math Stack Exchange (MSE): http://math.stackexchange.com/questions/54506/is-this-batman-equation-for-real/54568#54568 Here's the image: |dw:1435886055793:dw| http://i.stack.imgur.com/VYKfg.jpg I tried to graph it on Desmos: https://www.desmos.com/calculator/cscx2zcrlf Graphing each factor separately turns out well, however when I multiply all factors, graph won't appear. I think Desmos just choke on it, so I tried something simple; https://www.desmos.com/calculator/enxuzekis6 Yet it doesn't show anything... So apparently image above is not true. My questions are: $\Large 1)$ Is there any way to union relations? By "union," I mean in $\mathbb R^2$, if you union $f(x,y)=0$ and $g(x,y)=0$, then you would have new union relation $U(x,y)=0$, which if you graph it, then $f(x,y)=0$ and $g(x,y)=0$ would both be graphed simultaneously. From image, it's $U(x,y) = f(x,y)g(x,y)=0$, but it seems that it is not true. $\Large 2)$ Why does no one seem to notice that image is not true in MSE question?

anonymous · Answer

A relation is a set, so obviously you could union two relations.

geerky42 · Answer

Yeah I know. Not sure what's correct word for that, but let's just stick with "union"

By "union," I mean saying if you graph $f(x,y)=0$ and $g(x,y)=0$, you would see something on xy plane. If we "union" these relations, then we would have new relation $U(x,y)=0$, such that if you graph $U(x,y)$, then you would see same thing as if you graph $f(x,y)=0$ and $g(x,y)=0$ separately at the same time.

geerky42 · Answer

From shown image, you just multiply relations, but to me, it doesn't work.

just_one_last_goodbye · Answer

In my opinion it doesn't work :/ very complex and in testing ur not going to really make a perfect batman sign on the graph xD

anonymous · Answer

We are such math nerds XD

geerky42 · Answer

For example; saying we have $f(x,y) = x^2+y^2 -1= 0$ and  $g(x,y) = (x+2)^2+y^2-1=0$

Then $U(x,y)$ would graph this:|dw:1435887037303:dw|

Exactly what is $U(x,y)$? and how can I "combine" f(x,y) and g(x,y) to form U(x,y)?