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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 7

Find the domain of each rational function. f(x)=(x+7)/(x2+49)

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Identify the rational function given: \(f(x) = \frac{x+7}{x^{2} + 49}\).
Recall that the domain of a rational function includes all real numbers except where the denominator is zero, because division by zero is undefined.
Set the denominator equal to zero to find values to exclude: \(x^{2} + 49 = 0\).
Solve the equation \(x^{2} + 49 = 0\) by isolating \(x^{2}\): \(x^{2} = -49\).
Since \(x^{2} = -49\) has no real solutions (because a square cannot be negative in the real number system), the denominator is never zero for any real \(x\), so the domain is all real numbers.

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주요 개념

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

Domain of a Function

The domain of a function is the set of all possible input values (x-values) for which the function is defined. For rational functions, the domain excludes any x-values that make the denominator zero, as division by zero is undefined.
추천 영상:
3:51
Domain Restrictions of Composed Functions

Rational Functions

A rational function is a ratio of two polynomials, expressed as f(x) = P(x)/Q(x). Understanding the behavior of the numerator and denominator polynomials is essential, especially identifying values that cause the denominator to be zero.
추천 영상:
6:04
Intro to Rational Functions

Solving Quadratic Equations

To find values that make the denominator zero, you solve the quadratic equation Q(x) = 0. Techniques include factoring, completing the square, or using the quadratic formula to determine if real roots exist that restrict the domain.
추천 영상:
06:08
Solving Quadratic Equations by Factoring