Math Problem Statement

Use function composition to determine f(g(x)) and g(f(x)) for the functions: f(x) = 3x + 1 and g(x) = x^2 + 1.

Solution

The question in the image appears to be about finding the function composition of two functions. Here's the content from the image:


Use function composition to determine f(g(x))f(g(x)) and g(f(x))g(f(x)) for the functions:

f(x)=3x+1andg(x)=x2+1f(x) = 3x + 1 \quad \text{and} \quad g(x) = x^2 + 1


Let's compute both f(g(x))f(g(x)) and g(f(x))g(f(x)).

1. Finding f(g(x))f(g(x)):

Given that f(x)=3x+1f(x) = 3x + 1 and g(x)=x2+1g(x) = x^2 + 1, to find f(g(x))f(g(x)), we substitute g(x)g(x) into f(x)f(x):

f(g(x))=f(x2+1)f(g(x)) = f(x^2 + 1) Now substitute x2+1x^2 + 1 into f(x)=3x+1f(x) = 3x + 1: f(g(x))=3(x2+1)+1=3x2+3+1=3x2+4f(g(x)) = 3(x^2 + 1) + 1 = 3x^2 + 3 + 1 = 3x^2 + 4

2. Finding g(f(x))g(f(x)):

To find g(f(x))g(f(x)), we substitute f(x)f(x) into g(x)g(x): g(f(x))=g(3x+1)g(f(x)) = g(3x + 1) Now substitute 3x+13x + 1 into g(x)=x2+1g(x) = x^2 + 1: g(f(x))=(3x+1)2+1g(f(x)) = (3x + 1)^2 + 1 First, expand (3x+1)2(3x + 1)^2: (3x+1)2=9x2+6x+1(3x + 1)^2 = 9x^2 + 6x + 1 Now, add 1: g(f(x))=9x2+6x+1+1=9x2+6x+2g(f(x)) = 9x^2 + 6x + 1 + 1 = 9x^2 + 6x + 2

Final Results:

  • f(g(x))=3x2+4f(g(x)) = 3x^2 + 4
  • g(f(x))=9x2+6x+2g(f(x)) = 9x^2 + 6x + 2

Would you like a deeper explanation or have any questions?

Here are some related questions:

  1. What is the general concept of function composition in mathematics?
  2. Can the composition of two functions be commutative, i.e., is f(g(x))f(g(x)) always equal to g(f(x))g(f(x))?
  3. How does the degree of a polynomial change after composing two functions?
  4. How would you compute f(f(x))f(f(x)) or g(g(x))g(g(x)) for these functions?
  5. What happens to the function composition when one of the functions is a linear function?

Tip: Always expand expressions carefully when performing function composition to avoid algebraic errors.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra

Formulas

f(g(x)) = f(x^2 + 1) = 3(x^2 + 1) + 1 = 3x^2 + 4
g(f(x)) = g(3x + 1) = (3x + 1)^2 + 1 = 9x^2 + 6x + 2

Theorems

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Suitable Grade Level

Grades 9-12