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Index

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College Algebra

Definition

In the context of radicals, the index specifies the root being taken. For example, in $\sqrt[n]{x}$, 'n' is the index and indicates an n-th root.

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5 Must Know Facts For Your Next Test

  1. The default index for square roots is 2 and is often not written explicitly.
  2. When the index is 3, it refers to a cube root.
  3. The index must be a positive integer greater than or equal to 2.
  4. Changing the index changes which root you are taking; for example, $\sqrt[4]{16}$ means finding the fourth root of 16.
  5. In rational exponents, an expression like $x^{m/n}$ corresponds to $\sqrt[n]{x^m}$ where 'n' is the index.

Review Questions

  • What is the default value of an omitted index in a radical?
  • How does changing the index from 3 to 4 affect the radical expression?
  • In $\sqrt[5]{32}$, what does '5' represent?
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