Square Roots a is a square root of b if and only if Example 1 3 is a square root of 9, since - 3 is also a square root of 9, since Thus, 9 has two square roots, -3 and 3.
Example 2 The number 0 has only one square root, which is 0 since
Sometimes there are no square roots of a number. Example 3: There are no square roots of –16 since there are no numbers a such that Note that neither 4 nor – 4 will work.
Radical notation Radical symbol Square root of a The expression that appears under the radical sign, a in this case, is called the radicand. When radical notation is used, the result is the principal square root, which is the non-negative root.
Example 4 Simplify: There are two square roots of 25, - 5 and 5. The principal second root is the non-negative root, or 5. Therefore,
Example 5 Simplify Reasoning Note that while it is also true that we want the principal (nonnegative) root.
Example 6 Simplify Reasoning
Example 7 Simplify Reasoning is undefined.
Example 8 Simplify Reasoning
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