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teachings (mander.xyz)
submitted 1 year ago by [email protected] to c/[email protected]
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[-] [email protected] 113 points 1 year ago
[-] [email protected] 72 points 1 year ago

Eh, not really. It's been a while, but I'm pretty sure the rule in algebra when solving for a squared variable like this is to use ± for exactly that reason.

[-] [email protected] 23 points 1 year ago* (last edited 1 year ago)

just wait for n-th roots of imaginary numbers :)

[-] [email protected] 94 points 1 year ago* (last edited 1 year ago)

-3 id the hidden dark version character of the solution, like evil ryu or devil jin.

[-] [email protected] 12 points 1 year ago

just a glimpse into my dark and twisted mind

[-] [email protected] 7 points 1 year ago

But for the Joker, that's the real solution.

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[-] [email protected] 52 points 1 year ago* (last edited 1 year ago)

Doesn’t x also equal -3?

[-] [email protected] 18 points 1 year ago
[-] [email protected] 30 points 1 year ago

Uhm, actually 🤓☝️!

Afaik sqrt only returns positive numbers, but if you're searching for X you should do more logic, as both -3 and 3 squared is 9, but sqrt(9) is just 3.

If I'm wrong please correct me, caz I don't really know how to properly write this down in a proof, so I might be wrong here. :p
(ps: I fact checked with wolfram, but I still donno how to split the equation formally)

[-] [email protected] 25 points 1 year ago* (last edited 1 year ago)

You're correct. The square root operator only returns the principal root (the positive one).

So if x^2 = 9 then x = ±√9 = ±3

That's why in something like the quadratic formula we all had to memorize in school its got a "plus or minus" in it: -b ± √...(etc)

[-] [email protected] 9 points 1 year ago

Thanks, I haven't connected the dots to that (+-) sign and this problem.

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[-] [email protected] 21 points 1 year ago* (last edited 1 year ago)

x^2 = 9

<=>

|x| = sqrt(9)

would be correct. That way you get both 3 and -3 for x.

That's the way your math teacher would do it. So the correct version of the statement in the picture is: "if x^2 = 9 then abs(x) = 3"

[-] [email protected] 4 points 1 year ago

Cool! Makes sense to me. Honestly, I've never done it this way, but it's so clean. Love it. Thanks.

[-] [email protected] 13 points 1 year ago

Fund the sqrter!

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[-] [email protected] 20 points 1 year ago

Also math teacher...

"Show your work"

[-] [email protected] 18 points 1 year ago

Middle school math memes

[-] [email protected] 16 points 1 year ago

The number of solutions/roots is equal to the highest power x is raised to (there are other forms with different rules and this applies to R and C not higher order systems)

Some roots can be complex and some can be duplicates but when it comes to the real and complex roots, that rule generally holds.

[-] [email protected] 4 points 1 year ago* (last edited 1 year ago)

I think you can make arbitrarily complicated roots if you move over to G^n^ which includes the R and C roots...

For example the grade 4 blade (3e1e2e3e4)^2 = 9 in G^4^

Complex roots are covered because the grade 2 blade (e1e2)^2 = -1 making it identical to i so G^n^ (n>=2) includes C.

G^n^ also includes all the scalars (grade 0 blades) so all the real roots are included.

G^n^ also includes all the vectors (grade 1 blades) so any vector with length 3 will square to 9 because u^2 = u dot u = |u|^2 where u is a vector.

All blades will square to a scalar but blades are not the only thing in G^n^ so things get weird with the multivectors(sums of different grades). Any blade with grade n%4 < 2 will square to a positive scalar and the other grades will square to a negative, with the abs of the scalar equal to the norm^2^ of the blade. Can pretty much just make as many roots as you want if you are willing to move into higher dimensional spaces and use a way cooler product.

[-] [email protected] 8 points 1 year ago

You lost me at "arbitrarily complicated," sorry.

[-] [email protected] 8 points 1 year ago

Lost me at "I think". I don't, apparently.

[-] [email protected] 6 points 1 year ago

I don't think therefore I never was

[-] [email protected] 7 points 1 year ago

I wish it was that easy! I stopped thinking and I'm still stuck here... Stupid Descartes

[-] [email protected] 3 points 1 year ago

I thought this would be related to quaternions, octonions etc. but no, it's multivectors and wedge products. Very neat, I didn't know you could use them like that.

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[-] [email protected] 15 points 1 year ago

Me, a statistician: "if chi-square equals 9 then chi equals 3... What??"

[-] [email protected] 13 points 1 year ago

My teacher explained as sqrt(poop^2) = abs(poop). Yes, he wrote poop on the blackboard.

[-] [email protected] 3 points 1 year ago

He should have drawn a pile of poop instead 💩 (preferably without a face)

[-] [email protected] 11 points 1 year ago

Oh, I know this one! It's pi!

[-] [email protected] 12 points 1 year ago

What, no. It's... Eh close enough.

[-] [email protected] 4 points 1 year ago

TAU IS BETTER

/obligatory

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[-] [email protected] 8 points 1 year ago
[-] [email protected] 5 points 1 year ago

Absolutely.

[-] [email protected] 5 points 1 year ago

Adding 3 on both sides

3-3=3+3

0 = 6

1•0 = 6

1 = 6/0

1 = inf

Multiplying e^(iπ) on both sides,

e^(iπ) = - inf

iπ = ln|-inf|

π = ln|-inf| ÷ i

[-] [email protected] 2 points 1 year ago

1/0 isn't infinity though.

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[-] [email protected] 4 points 1 year ago

I know the math but I still feel like I'm out of the loop somehow?

[-] [email protected] 5 points 1 year ago

There's nothing more to this than linking the star wars quote to the -3. That's it lol

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[-] [email protected] 5 points 1 year ago

(-3)^2 = 9 as well

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this post was submitted on 17 Apr 2024
782 points (98.0% liked)

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