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Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 156

Rationalize each denominator. Assume all variables represent nonnegative numbers and that no denominators are 0.
a(a+b)1\(\frac{a}{(\surd a+b)-1}\)

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1
Identify the expression to rationalize: \(\frac{a}{\sqrt{a} + b} - 1\).
Focus on rationalizing the denominator of the fraction \(\frac{a}{\sqrt{a} + b}\). To do this, multiply both the numerator and denominator by the conjugate of the denominator, which is \(\sqrt{a} - b\).
Multiply numerator and denominator by \(\sqrt{a} - b\): \(\frac{a}{\sqrt{a} + b} \times \frac{\sqrt{a} - b}{\sqrt{a} - b} = \frac{a(\sqrt{a} - b)}{(\sqrt{a} + b)(\sqrt{a} - b)}\).
Simplify the denominator using the difference of squares formula: \((\sqrt{a} + b)(\sqrt{a} - b) = (\sqrt{a})^2 - b^2 = a - b^2\).
Rewrite the expression as \(\frac{a(\sqrt{a} - b)}{a - b^2} - 1\) and then combine the terms over a common denominator if needed.

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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 square roots or irrational numbers from the denominator of a fraction. This is done by multiplying the numerator and denominator by a conjugate or an appropriate expression to create a rational denominator, simplifying the expression.
추천 영상:
02:58
Rationalizing Denominators

Conjugates of Binomials

The conjugate of a binomial expression like (√a + b) is (√a - b). Multiplying a binomial by its conjugate uses the difference of squares formula, which removes the square root terms in the denominator, making it rational and easier to work with.
추천 영상:
05:33
Complex Conjugates

Properties of Square Roots and Nonnegative Variables

Since variables represent nonnegative numbers, square roots like √a are defined and real. This assumption ensures that expressions involving square roots are valid and simplifies the process of rationalization without considering complex numbers.
추천 영상:
02:20
Imaginary Roots with the Square Root Property