What is the principal or(postive)square root of a number n

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.



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.



means the negative square root of 4 which is -2.