The principal root of a number is the positive real square root of the number - if it exists.
Since -25 is negative, it does not have a real square root. Its square roots are the imaginary numbers +/-5i where i is the [imaginary] square root of -1. i is neither positive nor negative and so neither +5i nor -5i is a principal root.
The square of 25 is 25 x 25 = 625. The principal square root of 25 is 5.
It is: 2/5
A number will have both a positive and negative square root 5 x 5 = 25 and -5 x -5 = 25.
sqrt(15) + sqrt(25) = 5 + sqrt(15) = 8.873 (using principal roots only).
The principal root is the positive square root.
It is 25
It is +25
The square of 25 is 25 x 25 = 625. The principal square root of 25 is 5.
That refers to the positive root, at least if you take the root of a positive number. For example, 25 has two square roots - two numbers which, when squared, give 25. The positive one (+5) is called the principal square root (or 2nd. root).
It is: 2/5
A number will have both a positive and negative square root 5 x 5 = 25 and -5 x -5 = 25.
Restricting the discussion to real numbers for now. In this case, the square root is only defined for non-negative numbers; the principal square root of a positive number is the POSITIVE square root. For example, both +5 and -5 are square roots of 25, since both - when squared - give you 25. But the positive square root (+5) is called the principal square root, and if you write the square root symbol, that's the number usually meant.
The principal square root is the non-negative square root.
sqrt(15) + sqrt(25) = 5 + sqrt(15) = 8.873 (using principal roots only).
The principal root is the positive square root.
sqrt(25)*2 = 5*2 = 10 (using only the principal sq rt).
The principal (positive) square root of 225 is 15.