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Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 108

Solve each equation for the specified variable. (Assume all denominators are nonzero.) 1/R=1/r_1 + 1/r_2, for R

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Start with the given equation: \(1\/R = 1\/r_1 + 1\/r_2\).
To combine the terms on the right side, find a common denominator, which is \(r_1 r_2\), so rewrite the right side as \(\frac{r_2}{r_1 r_2} + \frac{r_1}{r_1 r_2}\).
Add the fractions on the right side: \(\frac{r_2 + r_1}{r_1 r_2}\), so the equation becomes \(1\/R = \frac{r_1 + r_2}{r_1 r_2}\).
To solve for \(R\), take the reciprocal of both sides, remembering that taking the reciprocal flips the fraction: \(R = \frac{r_1 r_2}{r_1 + r_2}\).
This expression gives \(R\) in terms of \(r_1\) and \(r_2\), completing the solution.

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주요 개념

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

Solving Equations for a Specific Variable

This involves isolating the desired variable on one side of the equation. Techniques include using inverse operations such as addition, subtraction, multiplication, division, and applying algebraic manipulations to rewrite the equation in terms of the specified variable.
추천 영상:
05:28
Equations with Two Variables

Working with Rational Expressions

Rational expressions are fractions that contain variables in the numerator, denominator, or both. Understanding how to manipulate these expressions, including finding common denominators and simplifying complex fractions, is essential for solving equations involving sums of reciprocals.
추천 영상:
02:58
Rationalizing Denominators

Reciprocals and Their Properties

A reciprocal of a number is 1 divided by that number. Recognizing how to combine and manipulate sums of reciprocals, such as 1/R = 1/r_1 + 1/r_2, helps in rewriting the equation and solving for the variable of interest by inverting or rearranging terms.
추천 영상:
5:36
Change of Base Property