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[Darvi]

...I have no Idea where those came from. The one you just posted seems to be a miniaturized version of the x=-b/2a picture. Probably saved them by accident or something when I tried to copy these stupid pictures from wikipedia.

[Tellemurius]

x equals negative b, plus and minus the square root, b square minus 4 with a and c, all over 2 a. (shitty quadratic formula song)

[Leafsnail]

My maths teacher threatens to send people who use mneumonics out of the class :x.

_{Well, jokingly.  He really doesn't like them.}

[Tellemurius]

my teacher was the one that invented it so...

surprised i even remembered it 4 years ago

(i never used it)

[lordnincompoop]

my teacher was the one that invented it so...

Doubt it.

As for mnemonics, I've only had one such encounter. It was with a sub teacher, who used it to get us to remember Stoichiometry, and kitty-corners.

...I have to find that guy again.

[Tellemurius]

i wouldn't doubt it, she was fricking weird.

[Zrk2]

My grade 10 teacher dressed up like a gangster to sing it.

WORSE DAY EVER.

[Tellemurius]

My grade 10 teacher dressed up like a gangster to sing it.

WORSE DAY EVER.

yea that sums it up XD

[Zrk2]

...Mrs. Bernard? ...

[Tellemurius]

no, Mrs. Winkel and i had her at 9th grage.

[Zrk2]

Oh, ok. THought we might be at the same school for a second. Crisis averted.

[Tellemurius]

if your 16 then thats impossible.

[KaminaSquirtle]

And another one that's been bugging me:
Show that χ(G)+χ(G bar) >= 2*square root(n), where n is the number of vertices in G, and G bar is the complement of G (has exactly the edges that G doesn't).

Any ideas would be greatly appreciated.   Mostly I'm having trouble relating the chromatic number of G bar to the chromatic number of G.

[Sowelu]

Hmmm, that's a tricky one.

Okay.  Every vertex in G is going to be connected to at least n/2 vertices in either G or G bar.  Either G or G bar is going to have at least half of the possible edges in its set.

We know the chromatic number for a fully connected graph (X(G) = n), X(G bar) = 0).  We don't know the number for a half-connected graph (X(G) ~= X(G bar) = ).  If my intuition is right, X(G) for a half-connected G is going to be >= 2*square root(n) by itself...which will make your life a lot easier if it's true.

What's the lowest possible chromatic number for a graph that has only half of its possible edges, rounded up?

[Heron TSG]

Okay, so my Calculus class is doing a section on Optimization. I have it down fairly well, but this type of problem is giving me trouble. I need to find the shortest possible straight plank (the orange line) that can touch both the building and the ground to the left of the 8 foot high wall that is 27 feet away.



Here is what I know.

B²= (27 + X)² + H²
B= ((27 + X)² + H²)^.5
H= (B² - (27 + X)²)^.5
X= [(B² - H²)^.5] - 27