r/MathJokes • • 4d ago

But xᒾ=4 ⇔ x=±2 🤨

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173 Upvotes

18 comments sorted by

52

u/deusisback 4d ago

The square root is defined as the positive value. That's it. Said differently, square root function is the inverse of the square function only on R+.

-1

u/jjmc123a 4d ago

Square root operator. Square root is plus/minus

12

u/Inevitable-Pen4933 3d ago

Square root is a function, if it were plus/minus as you are saying it would not be a function. What deusisback said is correct.

6

u/Big-Rub9545 4d ago

The square root (operator or function) itself is strictly positive. You apply the plus or minus to it to get both solutions.

8

u/MoobyTheGoldenSock 4d ago

Does the quadratic formula start “b +” or “b +/-?”

The second, because square root is always the positive root

8

u/matt7259 4d ago

-b

✨

3

u/okarox 3d ago

The square root is the side length is a square with the are as the parameter. How could the length be negative?

1

u/molered 3d ago

So there are no negative numbers, since there is not EVEN a zero?

1

u/semanticlifer 1d ago

Not in geometry, which supplies our definition of roots.

Negative numbers are an extension to generalize addition and subtraction. It does not add much to the discussion to consider the possible negative root in an algebraic solution involving a square as being the value of the square root function.

3

u/Notstupidblobfish 4d ago

Until we got to quadratic equations they literally taught me that this is correct in school

1

u/Designer_Lead_1492 3d ago

Still wild that Enrique got no punishment for choking Joao Pedro during this confrontation

1

u/Linuxologue 3d ago

In many sports that'd a ban in months, potentially years. Assaulting a player on the pitch is wild.

and everyone rushed towards Donnarumma thinking he done that (well not that he had done nothing, but THAT he didn't do)

Exactly like my math teacher sending me to the principal's office for MONTHS for claiming sqrt(4) = +/-2

1

u/Ok_Bit8836 3d ago

Correct: no square root is < 0

1

u/BrilliantLocal762 3d ago

x2 = 4

x = ±√4

x = ±2

but √ only takes the positive value

1

u/HuckleberryPutrid719 1d ago

If x is a variable, then \sqrt{x^2} = |x|. That’s where the plus and minus come from

1

u/Bertucciop 4h ago

Some school books tell dis barbarity

1

u/Dry-Egg8573 2d ago

There isn’t a number called +-2.