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Ch. 3 - Polynomial and Rational Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
4장, 문제 68

Solve each inequality in Exercises 65–70 and graph the solution set on a real number line. 1/(x + 1) > 2/(x - 1)

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Start by writing the inequality clearly: \(\frac{1}{x + 1} > \frac{2}{x - 1}\).
Bring all terms to one side to have zero on the other side: \(\frac{1}{x + 1} - \frac{2}{x - 1} > 0\).
Find a common denominator, which is \((x + 1)(x - 1)\), and combine the fractions: \(\frac{(x - 1) - 2(x + 1)}{(x + 1)(x - 1)} > 0\).
Simplify the numerator: \((x - 1) - 2(x + 1) = x - 1 - 2x - 2 = -x - 3\), so the inequality becomes \(\frac{-x - 3}{(x + 1)(x - 1)} > 0\).
Determine the critical points by setting numerator and denominator equal to zero: numerator \(-x - 3 = 0\) gives \(x = -3\), denominator \((x + 1)(x - 1) = 0\) gives \(x = -1\) and \(x = 1\). Use these points to test intervals on the number line to find where the inequality holds.

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주요 개념

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

Solving Rational Inequalities

Rational inequalities involve expressions with variables in the denominator. To solve them, first bring all terms to one side to form a single rational expression, then determine where this expression is positive or negative by analyzing its critical points.
추천 영상:
02:58
Rationalizing Denominators

Finding Critical Points and Domain Restrictions

Critical points occur where the numerator or denominator equals zero. These points divide the number line into intervals to test. Also, values that make the denominator zero are excluded from the domain, as they cause undefined expressions.
추천 영상:
3:51
Domain Restrictions of Composed Functions

Graphing Solution Sets on a Number Line

After determining intervals where the inequality holds, represent the solution set on a real number line. Use open or closed circles to indicate whether endpoints are included or excluded, and shade the regions that satisfy the inequality.
추천 영상:
02:35
Graphing Lines in Slope-Intercept Form