Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
0. Review of College Algebra
Rationalizing Denominators
Problem 119
Textbook Question
Rationalize each denominator. See Example 8. 5 —— √5
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1
Identify the need to rationalize the denominator, which involves eliminating the square root from the denominator.
Multiply both the numerator and the denominator by the conjugate of the denominator. In this case, multiply by \( \sqrt{5} \).
Write the expression as \( \frac{5}{\sqrt{5}} \times \frac{\sqrt{5}}{\sqrt{5}} \).
Simplify the numerator: \( 5 \times \sqrt{5} = 5\sqrt{5} \).
Simplify the denominator: \( \sqrt{5} \times \sqrt{5} = 5 \).
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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 √5, you would multiply by √5/√5.
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Rationalizing Denominators
Properties of Square Roots
Understanding the properties of square roots is essential for rationalizing denominators. The key property is that the square root of a product is the product of the square roots, i.e., √(a*b) = √a * √b. This property allows us to manipulate expressions involving square roots effectively, facilitating the rationalization process.
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Imaginary Roots with the Square Root Property
Simplifying Fractions
Simplifying fractions is the process of reducing a fraction to its simplest form, where the numerator and denominator have no common factors other than 1. This is important after rationalizing the denominator, as it ensures the final expression is as concise as possible. For instance, after rationalizing, you may need to simplify the resulting fraction to present the answer clearly.
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Solving Linear Equations with Fractions
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