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
Rationalize Denominator
Problem 52
Textbook Question
Rationalize the denominator.
3−15
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1
Identify the expression that needs rationalization: \( \frac{5}{\sqrt{3} - 1} \). The goal is to eliminate the square root from the denominator.
To rationalize the denominator, multiply both the numerator and the denominator by the conjugate of the denominator. The conjugate of \( \sqrt{3} - 1 \) is \( \sqrt{3} + 1 \).
Set up the multiplication: \( \frac{5}{\sqrt{3} - 1} \times \frac{\sqrt{3} + 1}{\sqrt{3} + 1} \). This is equivalent to multiplying by 1, so it does not change the value of the expression.
Multiply the numerators: \( 5 \times (\sqrt{3} + 1) = 5\sqrt{3} + 5 \).
Multiply the denominators using the difference of squares formula: \((\sqrt{3} - 1)(\sqrt{3} + 1) = (\sqrt{3})^2 - 1^2 = 3 - 1 = 2\).
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