Square Roots and Square-Root Functions
When we raise a number to the second power, we say that we have squared
the number. Sometimes we may need to find the number that was squared.
We call this process finding a square root of a number.
SQUARE ROOT
The number c is a square root of a if c2 = a.
PROPERTIES OF SQUARE ROOTS
Every positive real number has two real-number square roots.
The number 0 has just one square root, 0 itself.
Negative numbers do not have real-number square roots.*
PRINCIPAL SQUARE ROOT
The principal square root of a nonnegative number is its nonnegative
square root. The symbol √a represents the principal square root of a.
To name the negative square root of a, we can write – √a .