Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
0. Review of Algebra
Radical Expressions
2:32 minutes
Problem 149
Textbook Question
Textbook QuestionRationalize each denominator. Assume all variables represent nonnegative numbers and that no denominators are 0. 1/(2 + √5)
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Rationalizing the Denominator
Rationalizing the denominator involves eliminating any irrational numbers from the denominator of a fraction. This is typically achieved by multiplying both the numerator and the denominator by a suitable expression that will result in a rational number in the denominator. For example, to rationalize a denominator like (2 + √5), one would multiply by the conjugate (2 - √5).
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Rationalizing Denominators
Conjugates
The conjugate of a binomial expression is formed by changing the sign of the second term. For instance, the conjugate of (a + b) is (a - b). In the context of rationalizing denominators, using the conjugate helps to simplify expressions by utilizing the difference of squares, which eliminates the square root when multiplied together.
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Properties of Square Roots
Understanding the properties of square roots is essential for simplifying expressions involving them. Specifically, the property that √a * √a = a allows for the simplification of terms when rationalizing denominators. This property is crucial when multiplying by the conjugate, as it helps to transform the denominator into a rational number.
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