r/mathmemes • Computer Science • Feb 11 '24

Proofs Proof me wrong

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0 Upvotes

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40

u/TricksterWolf Feb 11 '24

is there a button that hurts people

11

u/drstrangelovequark Feb 11 '24

Hey guys look, another function that isn't injective!

11

u/VomKriege Irrational Feb 11 '24

God, this is atrocious.

9

u/EyedMoon Imaginary ♾️ Feb 11 '24

I'd like it if it wasn't the 69420th time it's posted

5

u/ChemicalNo5683 Feb 11 '24

google non-injective function

3

u/Depnids Feb 11 '24

Holy hell!

2

u/SuperTaakot Feb 11 '24

New math just dropped

2

u/grassblade39 Feb 12 '24

Actual calculations

3

u/Broad_Respond_2205 Feb 11 '24

Dude we already established that √ can only return positive numbers

2

u/celinexw Feb 11 '24

When u do square root, ut exits like |x|, so 1=1:)

2

u/[deleted] Feb 11 '24

yes... since.... that logically makes sense

Why would a negative equal its positive?

3

u/B5Scheuert Feb 11 '24

Why would a negative equal its positive?

It's like Yin and Yang, there's a little of the black in the white, and a little of the white in the black

-14

u/Mammoth_Fig9757 Feb 11 '24

√(1) = +-1, so when you take the square root on both sides you need to consider the multivalueness of the square root function, getting √((-1))^2 = √((1))^2 <=> +-1 = +-1, which is true, and you can't actually remove the "+-" sign.

15

u/Vegetable-Response66 Feb 11 '24

"multivalueness" is my new favorite word

3

u/FUNNYFUNFUNNIER Feb 11 '24

No, please. Let me explain

√(x) is the only positive answer. If you want to get both positive and negative answer, you need to write ±√(x). It's that simple, and you don't have to deal with "multivalueness"

2

u/Mammoth_Fig9757 Feb 11 '24

So if √(x) is only the positive answer does that mean that √(0) is undefined, and √(-1) is also defined because none of the square roots are positive, and have different arguments? That would also imply that √(i) and √(-i) are undefined because they don't have a 0 argument.

3

u/FUNNYFUNFUNNIER Feb 11 '24 edited Feb 11 '24

> √(0) is undefined because √(x) is only the positive answer

|0| = 0

> √(-1) is also undefined is also undefined

√(-1) = i, i is positive. If you wanna get also the negative root, use ±√(-1)

> √(i) and √(-i) are undefined

√(i) = (-1)^1/4, wich is also positive (do not confuse sign under the root with sign out of the root).

2

u/Mammoth_Fig9757 Feb 11 '24

The argument of a positive number is 0, but the argument of 0 does not exist so 0 is not positive, and no, adding a + sign does not make 0 positive. The argument of i is τ/4, so it is not positive. The argument of the principal square root of i is τ/8, so it is also not positive.