Questions: Which description best explains the domain of (g ∘ f)(x)?
the elements in the domain of f(x) for which g(f(x)) is defined
the elements in the domain of f(x) for which g(f(x)) is not zero
the elements in the domain of g(x) for which g(f(x)) is defined
the elements in the domain of g(x) for which g(f(x)) is not zero
Transcript text: Which description best explains the domain of $(g \circ f)(x)$ ?
the elements in the domain of $f(x)$ for which $g(f(x))$ is defined
the elements in the domain of $f(x)$ for which $g(f(x))$ is not zero
the elements in the domain of $g(x)$ for which $g(f(x))$ is defined
the elements in the domain of $g(x)$ for which $g(f(x))$ is not zero
Solution
Solution Steps
Step 1: Understand the Composition of Functions
The composition of functions \((g \circ f)(x)\) means that you first apply the function \(f\) to \(x\), and then apply the function \(g\) to the result of \(f(x)\). Therefore, for \((g \circ f)(x)\) to be defined, \(f(x)\) must be in the domain of \(g\).
Step 2: Determine the Domain of \((g \circ f)(x)\)
The domain of \((g \circ f)(x)\) consists of all \(x\) values that are in the domain of \(f\) such that \(f(x)\) is in the domain of \(g\). This means that we need to consider the elements in the domain of \(f(x)\) for which \(g(f(x))\) is defined.
Step 3: Analyze the Options
The first option states: "the elements in the domain of \(f(x)\) for which \(g(f(x))\) is defined." This matches our understanding from Step 2.
The second option states: "the elements in the domain of \(f(x)\) for which \(g(f(x))\) is not zero." This is incorrect because the domain is not concerned with whether \(g(f(x))\) is zero, but whether it is defined.
The third option states: "the elements in the domain of \(g(x)\) for which \(g(f(x))\) is defined." This is incorrect because it does not consider the domain of \(f(x)\).
The fourth option states: "the elements in the domain of \(g(x)\) for which \(g(f(x))\) is not zero." This is incorrect for the same reason as the second option.
Final Answer
The correct description is: \(\boxed{\text{the elements in the domain of } f(x) \text{ for which } g(f(x)) \text{ is defined}}\).