If f(x) = sqrt(x) and g(x) = x^2, what is the domain of f(g(x))?

Master the Praxis Mathematics (5165) Test. Enhance your skills with flashcards and practice questions, each with detailed explanations. Ace your exam confidently!

Multiple Choice

If f(x) = sqrt(x) and g(x) = x^2, what is the domain of f(g(x))?

Explanation:
When composing functions, the input must make the inner function’s output fall inside the outer function’s domain. The outer function f is defined for inputs ≥ 0. Since g(x) = x^2 is always nonnegative for any real x, every real x makes g(x) fall inside f’s domain. Therefore, the domain of the composition is all real numbers, (-∞, ∞). You can also see this by noting f(g(x)) = sqrt(x^2) = |x|, which exists for every real x.

When composing functions, the input must make the inner function’s output fall inside the outer function’s domain. The outer function f is defined for inputs ≥ 0. Since g(x) = x^2 is always nonnegative for any real x, every real x makes g(x) fall inside f’s domain. Therefore, the domain of the composition is all real numbers, (-∞, ∞). You can also see this by noting f(g(x)) = sqrt(x^2) = |x|, which exists for every real x.

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