Math Problem Statement

What is f(3)? Compute (f ∘ g)(5), (g ∘ f)(3), and (f⁻¹ ∘ g)(2) using the given functions f(x) and g(x) from a table.

Solution

Let's go through each part of the problem based on the image.

We have two functions f(x)f(x) and g(x)g(x) given in tabular form:

  • f(x)f(x):

    • f(1)=4f(1) = 4
    • f(2)=1f(2) = 1
    • f(3)=5f(3) = 5
    • f(4)=5f(4) = 5
    • f(5)=3f(5) = 3
  • g(x)g(x):

    • g(1)=4g(1) = 4
    • g(2)=4g(2) = 4
    • g(3)=2g(3) = 2
    • g(4)=2g(4) = 2
    • g(5)=3g(5) = 3

(a) What is f(3)f(3)?

From the table for f(x)f(x), we see that f(3)=5f(3) = 5.

(b) Compute (fg)(5)(f \circ g)(5), i.e., f(g(5))f(g(5)).

  • First, find g(5)g(5): From the table for g(x)g(x), we know that g(5)=3g(5) = 3.
  • Now, substitute into f(x)f(x): f(g(5))=f(3)f(g(5)) = f(3).
  • From part (a), f(3)=5f(3) = 5.

Thus, (fg)(5)=5(f \circ g)(5) = 5.

(c) Compute (gf)(3)(g \circ f)(3), i.e., g(f(3))g(f(3)).

  • First, find f(3)f(3): From part (a), f(3)=5f(3) = 5.
  • Now, substitute into g(x)g(x): g(f(3))=g(5)g(f(3)) = g(5).
  • From the table for g(x)g(x), g(5)=3g(5) = 3.

Thus, (gf)(3)=3(g \circ f)(3) = 3.

(d) Compute (f1g)(2)(f^{-1} \circ g)(2), i.e., f1(g(2))f^{-1}(g(2)).

  • First, find g(2)g(2): From the table for g(x)g(x), g(2)=4g(2) = 4.
  • Now, find f1(4)f^{-1}(4). This means we are looking for the value of xx such that f(x)=4f(x) = 4. From the table for f(x)f(x), f(1)=4f(1) = 4, so f1(4)=1f^{-1}(4) = 1.

Thus, (f1g)(2)=1(f^{-1} \circ g)(2) = 1.


Would you like more details or clarifications on any of the steps?

Here are 5 related questions for practice:

  1. What is g(f(4))g(f(4))?
  2. Compute (fg)(3)(f \circ g)(3).
  3. Find f1(5)f^{-1}(5).
  4. What is (gg)(1)(g \circ g)(1)?
  5. Compute f(g(4))f(g(4)).

Tip: For composite functions like (fg)(x)(f \circ g)(x), always evaluate the inside function first, then apply the outside function!

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Math Problem Analysis

Mathematical Concepts

Function Composition
Inverse Functions

Formulas

f(x)
g(x)
(f ∘ g)(x) = f(g(x))
(g ∘ f)(x) = g(f(x))
f⁻¹(x): Inverse of function f, where f(f⁻¹(x)) = x

Theorems

Function Composition
Inverse Function Theorem

Suitable Grade Level

Grades 10-12