Math Problem Statement

Find​ f(x) and​ g(x) such that

​h(x)=​(f◦​g)(x).

​h(x)=​(3−9​x)2

Suppose that

​g(x)=3−9x.

Solution

To find f(x)f(x) and g(x)g(x) such that h(x)=(fg)(x)h(x) = (f \circ g)(x), we use the definition of composition:

h(x)=f(g(x)).h(x) = f(g(x)).

We are given: h(x)=(39x)2andg(x)=39x.h(x) = (3 - 9x)^2 \quad \text{and} \quad g(x) = 3 - 9x.

Step 1: Substitute g(x)g(x) into h(x)h(x)

h(x)=f(g(x))=f(39x).h(x) = f(g(x)) = f(3 - 9x).

Thus: f(39x)=(39x)2.f(3 - 9x) = (3 - 9x)^2.

Step 2: Identify f(u)f(u) where u=g(x)u = g(x)

Let u=39xu = 3 - 9x. Then: f(u)=u2.f(u) = u^2.

Final Answer:

  • g(x)=39xg(x) = 3 - 9x,
  • f(x)=x2f(x) = x^2.

These satisfy the given composition h(x)=(fg)(x)h(x) = (f \circ g)(x).


Would you like a deeper explanation or a graph of these functions?
Here are 5 related questions to explore:

  1. What is the domain of f(x)f(x) and g(x)g(x)?
  2. How does the composition of functions work conceptually?
  3. What are examples of other h(x)h(x) functions and their decompositions?
  4. How does this apply to real-world problems, such as nested relationships?
  5. Can we reverse the process to find g(x)g(x) given f(x)f(x) and h(x)h(x)?

Tip: Always check the domain and range of each function in composition problems to ensure they are compatible.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra
Quadratic Functions

Formulas

h(x) = (f◦g)(x)
f(g(x))
f(u) = u²

Theorems

Composition of Functions

Suitable Grade Level

Grades 9-11