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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 59

Let f(x) = 2x - 5 g(x) = 4x - 1 h(x) = x² + x + 2. Evaluate the indicated function without finding an equation for the function. (fog) (0)

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Identify the functions involved: \(f(x) = 2x - 5\) and \(g(x) = 4x - 1\). The problem asks for \((f \circ g)(0)\), which means \(f(g(0))\).
First, evaluate the inner function \(g(0)\) by substituting \(x = 0\) into \(g(x) = 4x - 1\). This gives \(g(0) = 4(0) - 1\).
Simplify the expression for \(g(0)\) to find its value.
Next, take the result from \(g(0)\) and substitute it into the outer function \(f(x) = 2x - 5\). So, compute \(f(g(0)) = 2 \times g(0) - 5\).
Simplify the expression for \(f(g(0))\) to find the final value of \((f \circ g)(0)\).

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Key Concepts

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

Function Composition

Function composition involves applying one function to the result of another, denoted as (f ∘ g)(x) = f(g(x)). It means you first evaluate the inner function g at x, then use that output as the input for f. Understanding this process is essential to correctly evaluate composite functions without finding their explicit formula.
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Evaluating Functions at a Specific Input

Evaluating a function at a specific input means substituting the given value into the function's formula and simplifying. For composite functions, this requires careful step-by-step substitution, first evaluating the inner function at the input, then using that result in the outer function.
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Order of Operations in Function Evaluation

When evaluating composite functions, the order of operations is crucial: first compute the inner function's value, then apply the outer function to that result. This ensures accurate evaluation and avoids errors that arise from mixing up the sequence of substitutions.
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