In mathematics, a square root of a number x is a number y such that y² = x; in other words, a number y whose square (the result of multiplying the number by itself, or y ⋅ y) is x. For example, 4 and −4 are square roots of 16 because 4² = ( − 4 )² = 16.
Edit: I'm wrong lol, there is a difference between the square root function, which accepts two results, and the square root, or principal square root, which is a unique positive number
So close yet so far. If only you had read ONE more paragraph.
Every nonnegative real number x has a unique nonnegative square root, called the principal square root or simply the square root (with a definite article, see below), which is denoted by √x where the symbol "√" is called the radical sign or radix.
This sentence made no sense to me as it directly contradicted the previous one. But it's just a confusion on my part between the function called square root, which confusingly outputs two different numbers called "square roots", and "the" number called square root; I've edited my comment. Thanks for correcting me!
Yeah, I see how that can happen. Very confusing to have the same name for two things differentiated only by the use of a definite or indefinite article.
You can get the sqrt of a given y by looking at the x axis. E.g. the value of y=4 has two solutions, x=2 and x=-2. This however does not mean that the sqrt of -4 is also 2! If you look at graph you can see that there are no solutions for y less than 0.
sqrt(-1) , sqrt(-2) (i ill omit imaginary numbers here) and so on do not have a solution. There is nothing you can replace with such that x × x is < 0 because multiplying two negatives always nets a positive.