Jan 062012
•The next concept is the root of a number. Since 5 · 5 = 25, note that the reverse can be written as follows: √25 = 5.
–This is read as “the square root of 25 is 5.”
–The symbol √ is called the radical and the number 25 is called the radicand.
–The definition of a square root of a nonnegative number N is one of two identical numbers whose product is N.
•Every positive number N has two square roots:
–The principle or positive square root, √N.
–The negative square root, -√N.
•A whole number is called a perfect square if its square root is also a whole number.
–Example: √49 = 7 since 7 · 7 = 49.
The number 49 is a perfect square since its square root 7 is a whole number.
–Example: √8 = 2.83 since 2.83 · 2.83 = 8.
Thus, 8 is NOT a perfect square since 2.83 is NOT a whole number.
•The cube root of a number N is one of three identical numbers whose product is N.
–Example: The cube root of 8 equals 2 since 23 = 8.
–Note: The symbol 3√ is the notation used to represent the cube root.