Math Problem Statement

Find the domain and range of the composition f ∘ g from the given functions g and f, represented in the diagram.

Solution

Let's examine the functions gg and ff in the diagram.

We have two functions:

  1. g:Domain of gRange of gg: \text{Domain of } g \to \text{Range of } g
  2. f:Domain of fRange of ff: \text{Domain of } f \to \text{Range of } f

The composition of functions fgf \circ g means applying gg first, and then applying ff to the result of gg. We will identify the domain and range of this composition.

Function gg:

  • Domain: {1,2,3,4,5}\{1, 2, 3, 4, 5\}
  • Range: {5,7,8,9}\{5, 7, 8, 9\}

Function ff:

  • Domain: {5,7,8,9}\{5, 7, 8, 9\} (corresponds to the range of gg)
  • Range: {2,3,5}\{2, 3, 5\}

Finding the domain and range of fgf \circ g:

Domain of fgf \circ g:

The domain of the composition fgf \circ g is the set of all values in the domain of gg that get mapped to a value in the domain of ff. Since the range of gg is {5,7,8,9}\{5, 7, 8, 9\} and all these values are in the domain of ff, the domain of fgf \circ g is the same as the domain of gg.

Thus, the domain of fgf \circ g is: {1,2,3,4,5}\{1, 2, 3, 4, 5\}

Range of fgf \circ g:

To find the range, apply ff to the range of gg.

  • g(1)=7g(1) = 7, and f(7)=3f(7) = 3
  • g(2)=9g(2) = 9, and f(9)=5f(9) = 5
  • g(3)=8g(3) = 8, and f(8)=5f(8) = 5
  • g(4)=5g(4) = 5, and f(5)=2f(5) = 2
  • g(5)=7g(5) = 7, and f(7)=3f(7) = 3

Thus, the range of fgf \circ g is: {2,3,5}\{2, 3, 5\}

Final answers:

(a) Domain of fgf \circ g: {1,2,3,4,5}\{1, 2, 3, 4, 5\}

(b) Range of fgf \circ g: {2,3,5}\{2, 3, 5\}


Would you like further clarification on any part of the solution? Here are some follow-up questions to deepen understanding:

  1. What is the significance of the domain in a function composition?
  2. How do we determine if the composition fgf \circ g is defined for all inputs from gg?
  3. How would the range change if ff were defined differently?
  4. Can the domain and range of a function composition ever be equal?
  5. How does the concept of function composition apply to real-world problems?

Tip: In function composition, always ensure that the range of the first function aligns with the domain of the second function. This guarantees the composition is well-defined!

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Math Problem Analysis

Mathematical Concepts

Function Composition
Domain and Range

Formulas

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Theorems

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Suitable Grade Level

High School