"Roots" (or "radicals") are the "opposite" operation of applying exponents; we can "undo" a power with a radical, and we can "undo" a radical with a power. For instance, if we square 2, we get 4, and if we "take the square root of 4", we get 2; if we square 3, we get 9, and if we "take the square root of 9", we get 3. In mathematical notation, the previous sentence means the following:
2^{2} = 4, so √4 = 2
3^{2} = 9, so √9 = 3
The "√" symbol used above is called the "radical" symbol. The expression " √9 " is read as "root nine", "radical nine", or "the square root of nine".
