Skip to main content
Ch. 5 - Systems and Matrices
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
6장, 문제 25

Find the partial fraction decomposition for each rational expression. See Examples 1–4. (3x - 2)/((x + 4)(3x2 + 1))

검증된 단계별 안내
1
Identify the form of the partial fraction decomposition. Since the denominator is \((x + 4)(3x^2 + 1)\), where \(x + 4\) is a linear factor and \(3x^2 + 1\) is an irreducible quadratic factor, the decomposition will be of the form: \[ \frac{3x - 2}{(x + 4)(3x^2 + 1)} = \frac{A}{x + 4} + \frac{Bx + C}{3x^2 + 1} \] where \(A\), \(B\), and \(C\) are constants to be determined.
Multiply both sides of the equation by the common denominator \((x + 4)(3x^2 + 1)\) to clear the fractions: \[ 3x - 2 = A(3x^2 + 1) + (Bx + C)(x + 4) \] This step eliminates the denominators and allows us to work with polynomials.
Expand the right-hand side by distributing: \[ A(3x^2 + 1) = 3A x^2 + A \] and \[ (Bx + C)(x + 4) = Bx^2 + 4Bx + Cx + 4C \]. Combine like terms to write the right side as a polynomial in standard form: \[ (3A + B) x^2 + (4B + C) x + (A + 4C) \].
Set up a system of equations by equating the coefficients of corresponding powers of \(x\) from both sides. On the left, the polynomial is \(3x - 2\), which can be written as \(0x^2 + 3x - 2\). So, equate coefficients: \[ \text{Coefficient of } x^2: 0 = 3A + B \] \[ \text{Coefficient of } x: 3 = 4B + C \] \[ \text{Constant term}: -2 = A + 4C \].
Solve the system of equations for \(A\), \(B\), and \(C\). Once these constants are found, substitute them back into the partial fraction form \( \frac{A}{x + 4} + \frac{Bx + C}{3x^2 + 1} \) to complete the decomposition.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
12m
도움이 되었나요?

주요 개념

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

Partial Fraction Decomposition

Partial fraction decomposition is a method used to express a complex rational expression as a sum of simpler fractions. This technique is especially useful for integrating rational functions or solving equations. It involves breaking down the denominator into factors and assigning unknown constants to each fraction.
추천 영상:
4:07
Decomposition of Functions

Factoring and Types of Denominator Factors

Understanding the factorization of the denominator is crucial. Denominators can have linear factors (like x + 4) or irreducible quadratic factors (like 3x^2 + 1). Each type requires a different form in the decomposition: linear factors correspond to constants in the numerator, while quadratic factors require linear expressions.
추천 영상:
가이드 코스
04:36
Factor by Grouping

Setting Up and Solving Systems of Equations

After expressing the rational function as a sum of partial fractions with unknown coefficients, you multiply both sides by the denominator to clear fractions. Then, equate coefficients of corresponding powers of x to form a system of linear equations. Solving this system yields the values of the unknown constants.
추천 영상:
가이드 코스
5:48
Solving Systems of Equations - Substitution