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Ch. R - Algebra Review
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 133

Rationalize each denominator. See Example 8. (√2 - √3)/(√6 - √5)

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1
Identify the expression to rationalize: \(\frac{\sqrt{2} - \sqrt{3}}{\sqrt{6} - \sqrt{5}}\).
To rationalize the denominator, multiply both numerator and denominator by the conjugate of the denominator. The conjugate of \(\sqrt{6} - \sqrt{5}\) is \(\sqrt{6} + \sqrt{5}\).
Multiply numerator and denominator by \(\sqrt{6} + \sqrt{5}\): \(\frac{(\sqrt{2} - \sqrt{3})(\sqrt{6} + \sqrt{5})}{(\sqrt{6} - \sqrt{5})(\sqrt{6} + \sqrt{5})}\).
Use the difference of squares formula for the denominator: \((a - b)(a + b) = a^2 - b^2\), so the denominator becomes \(6 - 5\).
Expand the numerator by distributing each term: \((\sqrt{2})(\sqrt{6}) + (\sqrt{2})(\sqrt{5}) - (\sqrt{3})(\sqrt{6}) - (\sqrt{3})(\sqrt{5})\), then simplify each radical product.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Rationalizing the Denominator

Rationalizing the denominator involves eliminating any irrational numbers, such as square roots, from the denominator of a fraction. This is done to simplify the expression and make it easier to work with, often by multiplying numerator and denominator by a conjugate or an appropriate radical.
추천 영상:
2:58
Rationalizing Denominators

Conjugates of Binomials

The conjugate of a binomial expression a + b is a - b, and vice versa. Multiplying a binomial by its conjugate results in a difference of squares, which eliminates the square roots in the denominator, simplifying the expression to a rational number or simpler radical form.
추천 영상:
3:42
Rationalizing Denominators Using Conjugates

Difference of Squares Formula

The difference of squares formula states that (a + b)(a - b) = a² - b². This identity is crucial when rationalizing denominators involving binomials with radicals, as it helps remove the square roots by converting the product into a difference of squares, which is easier to simplify.
추천 영상:
2:25
Verifying Identities with Sum and Difference Formulas