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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Non è quello che usi tu?Cambia libro di testo
Capitolo 3, Problema 71

Find a. (fog) (x) b. the domain of f o g.
f(x) = √x, g(x) = x − 2

Guida verificata passo dopo passo
1
Step 1: Understand the composition of functions. The notation (fog)(x) represents the composition of f and g, which means f(g(x)). To find this, substitute g(x) into f(x).
Step 2: Substitute g(x) = x − 2 into f(x) = √x. This gives f(g(x)) = √(x − 2).
Step 3: Analyze the domain of the composition f(g(x)). Since f(x) = √x involves a square root, the expression inside the square root must be non-negative. Therefore, x − 2 ≥ 0.
Step 4: Solve the inequality x − 2 ≥ 0 to find the domain. Add 2 to both sides to get x ≥ 2.
Step 5: Conclude that the domain of f o g is all x-values such that x ≥ 2. In interval notation, this is [2, ∞).

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Function Composition

Function composition involves combining two functions, where the output of one function becomes the input of another. In this case, (f o g)(x) means applying g first and then applying f to the result of g. Understanding how to correctly perform this operation is essential for solving the problem.
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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 the composition of functions, the domain of f o g is determined by the values that g can take and the values that f can accept. Identifying these domains is crucial for ensuring that the composed function is valid.
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Square Root Function

The square root function, denoted as f(x) = √x, is defined only for non-negative values of x. This means that for f to be valid, the input must be greater than or equal to zero. Understanding the restrictions imposed by the square root function is vital for determining the overall domain of the composed function f o g.
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Imaginary Roots with the Square Root Property