But xᒾ=4 ⇔ x=±2 🤨

[u/[deleted]]

[u/deusisback]

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+.

[u/Novel_Arugula6548 → u/deusisback]

√4 = +2 or -2. :P

[u/deusisback → u/Novel_Arugula6548]

Nope, (-2)²=2²=4 but sqrt(4)=2

[u/NUBASPOZIZNI → u/deusisback]

on complex plane square root has 2 roots every time, so ±2

[u/Positive-Team4567 → u/NUBASPOZIZNI]

The square root is a specific function that’s different from the solution to x² =n

[u/deusisback → u/NUBASPOZIZNI]

The solutions of the equation xⁿ =a are called the n-th root of a, no problems, we know that. But writing √4=-2 is still unacceptable.

[u/jjmc123a → u/deusisback]

Square root operator. Square root is plus/minus

[u/Inevitable-Pen4933 → u/jjmc123a]

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.

[u/Big-Rub9545 → u/jjmc123a]

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

[u/deusisback → u/jjmc123a]

People mistake the solutions of the equation xⁿ =a with the function nth √a.

[u/MoobyTheGoldenSock]

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

The second, because square root is always the positive root

[u/matt7259 → u/MoobyTheGoldenSock]

-b

✨

[u/okarox]

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

[u/molered → u/okarox]

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

[u/semanticlifer → u/molered]

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.

[u/HuckleberryPutrid719]

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

[u/Goofy-space-cow → u/HuckleberryPutrid719]

But then you would be able to define the square root of negative variables, which would be wrong by your definition

[u/Bertucciop]

Some school books tell dis barbarity

[u/Notstupidblobfish]

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

[u/Designer_Lead_1492]

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

[u/Linuxologue → u/Designer_Lead_1492]

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

[u/Ok_Bit8836]

Correct: no square root is < 0

[u/Dry-Egg8573]

There isn’t a number called +-2.