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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 3, Problem 49a

Find ƒ+g, f−g, fg, and f/g. Determine the domain for each function. f(x) = √(x -2), g(x) = √(2-x)

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Step 1: Understand the problem. We are tasked with finding the sum (ƒ+g), difference (ƒ−g), product (ƒg), and quotient (ƒ/g) of the two functions ƒ(x) = √(x - 2) and g(x) = √(2 - x). Additionally, we need to determine the domain for each resulting function.
Step 2: Find ƒ+g. The sum of the two functions is given by (ƒ+g)(x) = ƒ(x) + g(x). Substituting the given functions, we have (ƒ+g)(x) = √(x - 2) + √(2 - x). To determine the domain, both square roots must be defined, meaning the expressions inside the square roots must be non-negative. Solve x - 2 ≥ 0 and 2 - x ≥ 0 to find the domain.
Step 3: Find ƒ−g. The difference of the two functions is given by (ƒ−g)(x) = ƒ(x) - g(x). Substituting the given functions, we have (ƒ−g)(x) = √(x - 2) - √(2 - x). The domain is the same as in Step 2, as it depends on the square root expressions being defined.
Step 4: Find ƒg. The product of the two functions is given by (ƒg)(x) = ƒ(x) * g(x). Substituting the given functions, we have (ƒg)(x) = √(x - 2) * √(2 - x). The domain is again determined by ensuring both square roots are defined, as in Step 2.
Step 5: Find ƒ/g. The quotient of the two functions is given by (ƒ/g)(x) = ƒ(x) / g(x). Substituting the given functions, we have (ƒ/g)(x) = √(x - 2) / √(2 - x). In addition to the domain restrictions from Step 2, we must also ensure that the denominator √(2 - x) ≠ 0. Solve 2 - x ≠ 0 to refine the domain.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Function Operations

Function operations involve combining two functions through addition, subtraction, multiplication, and division. For functions f and g, these operations are defined as (f + g)(x) = f(x) + g(x), (f - g)(x) = f(x) - g(x), (fg)(x) = f(x) * g(x), and (f/g)(x) = f(x) / g(x), provided that g(x) is not zero.
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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 functions involving square roots, the expression inside the square root must be non-negative. Therefore, determining the domain requires solving inequalities to find the valid x-values for each function.
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Square Root Functions

Square root functions, such as f(x) = √(x - 2) and g(x) = √(2 - x), are defined only for values that make the expression under the square root non-negative. This means that for f(x), x must be greater than or equal to 2, while for g(x), x must be less than or equal to 2. Understanding these constraints is crucial for determining the domain of the combined functions.
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