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/sci/ - Science & Math


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2598714 No.2598714 [Reply] [Original]

Let's see if /sci/ really does know math.

Here's a simple problem - without looking it up, within 30 seconds of seeing this post:
Post the quadratic formula
Post regardless of whether you have the answer or not.

If you have to cheat, you should/will be expelled from /sci/ / your school.

>> No.2598732

>memorising a formula that you have no idea what it actually means

You do know that it's actually the ability to derive it yourself algebraical which makes the difference between understanding and rote memory.

>> No.2598735

I have no fucking clue what a quadratic formula is.
Math is for roneries.

>> No.2598755

ax^2 + bx + c = 0

>> No.2598753

(-b + (b^2 - 4ac)^(1/2))/(2a)
(-b - (b^2 - 4ac)^(1/2))/(2a)

>> No.2598762

\frac{-b±\sqrt{b²-4ac}}{2a}

also testing jsmath

>> No.2598771

(-b +/- sqrt (b^2 - 4ac))/2a

>> No.2598776

>>2598732
I was never taught how to derive it, just to memorize it.

>> No.2598783

<div class="math">x = -{b \over 2a} \pm \sqrt{\left({b \over 2a}\right)^2 - {c \over a}}</div>

>> No.2598784

-b+-sqrtb^2-4ac/21

>> No.2598794

All algebraic formulas may be reduced to 1=1. Problems?

>> No.2598800

>>2598762
Ok I fail, is there any tutorial on this shit anywhere?

>> No.2598803

>>2598755
>>you are banished from sci

>> No.2598808

>>2598783
wat

>> No.2598809

>>2598776
Then you don't really know math

>> No.2598814

>>2598783
HOW YOU DO THAT

>> No.2598819

<div class="math">x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}</div>
27seconds

>> No.2598827

a^2+2ab+c^2=0

>> No.2598835
File: 240 KB, 4960x1754, sci_latex_tutorial.png [View same] [iqdb] [saucenao] [google]
2598835

>>2598814
Somebody asked for a tutorial?

>> No.2598841

>>2598776
Then you don't really know it and should leave /sci/

>> No.2598839

x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

>> No.2598844

(-b +/- sqrt (b^2-4(a)(c)))/2a

>> No.2598847

b +- (sqrt) ba/2ab

>> No.2598850

I don't know. I stopped doing maths a long time ago and usually never post in math threads.

>> No.2598853

x = (-b +- SQRT(-4AC + B^2))/2A

worked it out with paper+pen

>> No.2598855
File: 23 KB, 511x384, 1276919369481.jpg [View same] [iqdb] [saucenao] [google]
2598855

>>2598755
>>2598827

/sci/ certainly does lack reading comprehension.

>> No.2598865

>>2598783
>>2598819
ok, new to /sci/ here, how do u right out equations with the math script?

>> No.2598870

I cant be bothered to remeber that shit.
<span class="math">0=ax^2+bx+c=a(x+b/2a)^2+c-(b/2a)^2 \Rightarrow x=--b/2a \pm \sqrt{(b/2a)^2-c}[/spoiler]

>> No.2598876

>>2598835
<span class="math">\frac{-b±\sqrt{b^{2}-4ac}}{2a}[/spoiler]

Thanks, anon.

>> No.2598883

-b +- sqroot of b^2 + 4ac all over 2a

>> No.2598878

-(p/2)±sqrt((p/2)^2-q)

>> No.2598871
File: 47 KB, 404x306, 1296014082346.jpg [View same] [iqdb] [saucenao] [google]
2598871

>>2598841

>laymen aren't allowed in /sci/

>yfw

>> No.2598891

>mfw you guys haven't memorized the quintic formula

>> No.2598894

<span class="math">
(-∛((2b^3-9abc+27a^2 d+√((2b^3-9abc+27a^2 d)^2-4(b^2-3ac)^3 ))/2)-∛((2b^3-9abc+27a^2 d-√((2b^3-9abc+27a^2 d)^2-4(b^2-3ac)^3 ))/2)-b)/3a
[/spoiler]
cubic formula bitch

>> No.2598896

>>2598894
Now what in fucks name is that supposed to solve in the real world anyway?
Just look at it.

>> No.2598902

Solving for an item's position with changing acceleration.

>> No.2598908

>>2598865 how do u right out equations with the math script?
Ignoring the blatant typo, read my last post above.

>> No.2598914

not cheating
minus bee plus or minus the sqaure root of bee squared - 4 ay see all over 2a.

amirite?

>> No.2598920

But OP, why should I memorize the quadratic formula when I can look it up in seconds?

>> No.2598930

x=[-b+/-sqrt(b^2-4ac)]/(2a)

>> No.2598933

X equals negative B, plus or minus the square root of B squared minus four A C, all over 2 A.

>> No.2598938
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2598938

Clearly the answer is DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO DE GESO

>> No.2598940

Why not just complete the square? It's a lot more general and useful

>> No.2598946

x = (-b +/- √(b^2 - 4ac))/(2a)

I hate factoring

>> No.2598951

-b = +/- Sqroot of b^2 - 4ac / 2a

>> No.2598957

>>2598835
Appreciated

>> No.2599005 [DELETED] 

wat

>> No.2599011

>>2598714
x = [-b plus or minus the square root of (b^2 - 4ac)]/2a

where:

ax^2 + bx + c =0

>> No.2599032

x= -b + or - the square root of (b^2-4ac) all over 2a

>> No.2599049

lol i made a stupid song out of it

(pop goes the wheasel)

x equals negative b
plus or minus the square root
b square minus 4ac
all over 2a~

>> No.2599068

x = (-b +/- sqrt(b^2-4ac))/2a

>> No.2599225 [DELETED] 

wat

>> No.2599228

>>2599049
full of win

>> No.2599233

>>2599049
Mr. Mac?

>> No.2599236

>>2598835
that was the shit slowing down the posting earlier today

>> No.2599241

>read through entire thread
>expect to see actual discussion about quadratic formula, even though it's been done to death
>mfw all I see is a bunch of ego stroking 9th graders spamming the quadratic formula in butchered text trying to prove that they memorized a simple equation

ARHHGHARHGHARHHGAHRHGHARHHGHHAGHH

>> No.2599261

w/out looking at other posts:

x = -b +/- [sqrt(b^2 - 4ac)/2a]

>> No.2599273 [DELETED] 

<span class="math">\int_{a}^{b} f(x)dx = F(b) - F(a)[/spoiler]

>> No.2599303

>>2599049
Which reminds me, is there no youtube account or something that makes songs out of mathematical stuff? Surely there must.

>> No.2599312

(-B+-sqrt((B^2)-(4ac))/(2A)

+- means plus or minus

>> No.2599316

>>2598800

You just forgot the {math}{/math} script. With brackets, though.

It'll look like this:

<span class="math">\frac{-b±\sqrt{b²-4ac}}{2a}[/spoiler]

>> No.2599322

i made a song so I could remember it, but I haven't used it in so long so I wonder if it's right

x equals -b,
plus or minus the square root
of b squared minus 4ac
all over 2 a

sung in the tune of pop goes the weasel

>> No.2599347

y=mx^2+bx+c

>> No.2599406

I remember back in highschool

I learnt this, and since I was unattentive in class I talked about it to a friend, and he said there was a simple explanation/way to figure it out without looking it up.

Untill this day I didn't do any research about it. Anyone care to explain where this formula comes from?

>> No.2599439

<span class="math"> \mathrm{testing} [/spoiler]

>> No.2599475

>>2599233

does Mr. Mac have a thin beard, all black hair, and did he teach in Nova Scotia?

>> No.2599494

>>2599406
Complete the square

>> No.2599507

-b +/- ((b^2 - 4ac)^(1/2))/2a

Terrible notation but I think that's at least close to correct.

>> No.2599522

-b(plus or minus)(sqrt)(b^2-4ac)/2a

>> No.2599534

>>2599507

Terrible notation indeed, especially as it implies that only the part of the equation in brackets is being divided by 2a.

I'm starting to learn C++ and I used this when I was writing a program to solve quadratic equations:

root1 = (-B + sqrt(B*B-4*A*C))/(2*A);
root2 = (-B - sqrt(B*B-4*A*C))/(2*A);

>> No.2599550

x equals negative b plus or minus the square root of b squared minus four ac, all over 2a

>> No.2599562
File: 351 KB, 1599x1200, 1269997955782.jpg [View same] [iqdb] [saucenao] [google]
2599562

>>2599534
Your face when roots turn out to be complex or a is very small

>> No.2599566

>>2598783

a challenger appears

>> No.2599615

>>2599562

I only wrote it to solve the equation when there is at least one real root (it prints: "This equation has no real roots" when (B*B < 4*A*C)). It seems to work with values like 0.01 for A, although it messes up with extremely large or small numbers