Math Problem Statement

For each pair of functions f and g below, find f(g(x)) and g(f(x)). Then, determine whether f and g are inverses of each other.

Solution

Let's work through this problem step by step.

Problem Overview:

You are given pairs of functions f(x)f(x) and g(x)g(x), and you need to:

  1. Find f(g(x))f(g(x)) and g(f(x))g(f(x)) for each pair.
  2. Determine if ff and gg are inverses of each other by checking if f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x.

Let's address each part.

Part (a):

Functions:

  • f(x)=4x+0f(x) = \frac{-4}{x} + 0, which simplifies to f(x)=4xf(x) = \frac{-4}{x}
  • g(x)=4xg(x) = \frac{-4}{x}

Find f(g(x))f(g(x)):

Substitute g(x)g(x) into f(x)f(x): f(g(x))=f(4x)=44x=xf(g(x)) = f\left(\frac{-4}{x}\right) = \frac{-4}{\frac{-4}{x}} = x

Find g(f(x))g(f(x)):

Substitute f(x)f(x) into g(x)g(x): g(f(x))=g(4x)=44x=xg(f(x)) = g\left(\frac{-4}{x}\right) = \frac{-4}{\frac{-4}{x}} = x

Since both f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x, the functions are inverses of each other. Therefore, for part (a), you select "f and g are inverses of each other."

Part (b):

Functions:

  • f(x)=6x+3f(x) = 6x + 3
  • g(x)=x36g(x) = \frac{x - 3}{6}

Find f(g(x))f(g(x)):

Substitute g(x)g(x) into f(x)f(x): f(g(x))=f(x36)=6(x36)+3=(x3)+3=xf(g(x)) = f\left(\frac{x - 3}{6}\right) = 6\left(\frac{x - 3}{6}\right) + 3 = (x - 3) + 3 = x

Find g(f(x))g(f(x)):

Substitute f(x)f(x) into g(x)g(x): g(f(x))=g(6x+3)=(6x+3)36=6x6=xg(f(x)) = g(6x + 3) = \frac{(6x + 3) - 3}{6} = \frac{6x}{6} = x

Since both f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x, the functions are inverses of each other. Therefore, for part (b), you select "f and g are inverses of each other."


Would you like more details or have any specific questions?

Related Questions:

  1. What are the steps to verify if two functions are inverses?
  2. Can two functions be inverses if only one composition equals xx?
  3. How does the domain affect the invertibility of functions?
  4. How do transformations (like translations) affect inverse functions?
  5. How do you find the inverse of a quadratic function?

Tip:

For two functions to be inverses, f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x must both hold true for all values in their domains.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Inverse Functions
Algebra

Formulas

f(g(x)) = f(g(x))
g(f(x)) = g(f(x))
Inverse function rule: f(g(x)) = x and g(f(x)) = x

Theorems

Inverse Function Theorem

Suitable Grade Level

Grades 9-12