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Calculus IV
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Course: Algebra III / Intermediate Algebra
Topic: Radical Expressions
Subtopic: Operations III - Divide & Rationalize

Overview

Continue to expand your knowledge of radical expressions by dividing two radicals. When dividing radicals note that you may not leave a radical in the denominator of a fraction nor a fraction in the radicand. In either of these circumstances you must rationalize the denominator to eliminate the radical in the denominator.

Rule: When taking a root of a fraction, you can split it up into the root of the numerator over the root of the denominator. It's a good idea to reduce the fraction first though!

Rule: When dividing roots that have the same index, you can rewrite them as one big root with the radicands divided as one fraction underneath, and then simplify completely.

So sometimes you want to take the radical of a fraction and write it as a fraction of radicals and sometimes you want to take the fraction of radicals and write it as a radical of a fraction!

Rule: Never leave a fraction under a radical nor a radical in the denominator of a fraction. It is illegal! You must rationalize the denominator. This is an important process. Concentrate on rationalizing the denominator when the fraction has a square root in the bottom, but try some with higher roots too.

Objectives

By the end of this topic you should know and be prepared to be tested on:

Terminology

Define: the process of rationalizing the denominator

Text Notes

"Rationalizing the denominator" is an important concept, but concentrate on those that have single terms in the denominator (so you can SKIP the "conjugates" type). Watch the index carefully -- the higher it is the more complicated the rationalization process may become. SKIP "rationalizing the numerator".