The square root of number n is a number, r, that when squared equals n.
Each positive number has two square roots, a positive one and a negative one. The principal square root of a positive number is the positive square root.
For example, this of n = 4.
There are two numbers, r, that when squared equal 4.
The are 2 and -2, since 2^2 = 4 and (-2)^2 = 4.
4 has two square roots, a positive one and a negative one.
The positive square root, 2, is the principal square root of 4.
The symbol for the principal square root is the square root symbol.
[tex] \sqrt{4} [/tex]
means the principal square root of 4, which is 2.
If you mean the negative square root of 4, which is -2, then you must write a negative sign before the square root symbol.
[tex] -\sqrt{4} [/tex]
means the negative square root of 4 which is -2.
