Math Problem Statement

determine whether each pair of functions are inverses for g(x)=4x+1 and f(x)=-4x-1

Solution

To determine whether the given pair of functions are inverses, we need to check if:

  • f(g(x))=xf(g(x)) = x
  • g(f(x))=xg(f(x)) = x

Given:

  • g(x)=4x+1g(x) = 4x + 1
  • f(x)=4x1f(x) = -4x - 1

Step 1: Check f(g(x))f(g(x))

Substitute g(x)g(x) into f(x)f(x):

f(g(x))=f(4x+1)=4(4x+1)1f(g(x)) = f(4x + 1) = -4(4x + 1) - 1

Simplify:

f(g(x))=16x41=16x5f(g(x)) = -16x - 4 - 1 = -16x - 5

Since f(g(x))xf(g(x)) \neq x, the functions are not inverses based on this.

Step 2: Check g(f(x))g(f(x))

Substitute f(x)f(x) into g(x)g(x):

g(f(x))=g(4x1)=4(4x1)+1g(f(x)) = g(-4x - 1) = 4(-4x - 1) + 1

Simplify:

g(f(x))=16x4+1=16x3g(f(x)) = -16x - 4 + 1 = -16x - 3

Since g(f(x))xg(f(x)) \neq x, the functions are also not inverses based on this check.

Conclusion:

The functions g(x)=4x+1g(x) = 4x + 1 and f(x)=4x1f(x) = -4x - 1 are not inverses of each other.

Would you like more details on any step or further explanation?

Here are 5 related questions to expand your understanding:

  1. How do you algebraically verify if two functions are inverses?
  2. What is the geometric interpretation of inverse functions on a graph?
  3. Can you find the inverse of g(x)=4x+1g(x) = 4x + 1?
  4. How can you check for inverse functions using compositions of functions?
  5. What happens to the slopes of linear functions when they are inverses?

Tip: When finding the inverse of a function, swap xx and yy and then solve for yy to get the inverse.

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Math Problem Analysis

Mathematical Concepts

Algebra
Inverse Functions
Function Composition

Formulas

f(g(x))
g(f(x))

Theorems

Inverse Function Theorem

Suitable Grade Level

Grades 10-12