Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
3. Functions
Function Composition
Problem 4a
Textbook Question
In Exercises 1–30, find the domain of each function. g(x) = 2/(x+5)
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1
Identify the function: \( g(x) = \frac{2}{x+5} \).
Recognize that the domain of a function includes all real numbers except where the function is undefined.
For rational functions like \( \frac{2}{x+5} \), the function is undefined where the denominator is zero.
Set the denominator equal to zero and solve for \( x \): \( x + 5 = 0 \).
Solve the equation: \( x = -5 \). Therefore, the domain of \( g(x) \) is all real numbers except \( x = -5 \).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Domain of a Function
The domain of a function refers to the set of all possible input values (x-values) for which the function is defined. For rational functions, the domain is typically restricted by values that would make the denominator zero, as division by zero is undefined.
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Domain Restrictions of Composed Functions
Rational Functions
A rational function is a function that can be expressed as the ratio of two polynomials. In the case of g(x) = 2/(x+5), the numerator is a constant (2) and the denominator is a linear polynomial (x+5). Understanding the structure of rational functions is essential for determining their domains.
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Intro to Rational Functions
Finding Restrictions on the Domain
To find the domain of a function, one must identify any restrictions that prevent certain x-values from being included. For g(x) = 2/(x+5), the restriction occurs when the denominator equals zero, leading to the equation x + 5 = 0, which must be solved to find the excluded value.
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Domain Restrictions of Composed Functions
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