Math Problem Statement

Find

(

f

g

)

(

x

)

.

f

(

x

)

=

2

x

3

g

(

x

)

=

x

2

Solution

We are tasked with finding (fg)(x)(f \circ g)(x), which represents the composition of the functions f(x)f(x) and g(x)g(x).

Given:

  • f(x)=2x+3f(x) = 2x + 3
  • g(x)=x2g(x) = x^2

Steps to find (fg)(x)(f \circ g)(x):

  1. By definition, (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x)).
  2. Substitute g(x)g(x) into f(x)f(x). That means replacing the xx in f(x)f(x) with g(x)g(x).

So: (fg)(x)=f(g(x))=f(x2)(f \circ g)(x) = f(g(x)) = f(x^2)

  1. Now, substitute x2x^2 into f(x)=2x+3f(x) = 2x + 3:

f(x2)=2(x2)+3f(x^2) = 2(x^2) + 3

  1. Simplify the expression:

f(x2)=2x2+3f(x^2) = 2x^2 + 3

Thus, (fg)(x)=2x2+3(f \circ g)(x) = 2x^2 + 3.

Would you like further clarification or more details on function compositions?

Related questions:

  1. How do you find the composition of three functions?
  2. What are the domain and range of fgf \circ g given the functions f(x)=2x+3f(x) = 2x + 3 and g(x)=x2g(x) = x^2?
  3. How does the order of composition affect the result, i.e., f(g(x))f(g(x)) versus g(f(x))g(f(x))?
  4. What is the graphical interpretation of the composition of two functions?
  5. Can a composition of functions ever be undefined, and under what conditions?

Tip: Always check the domain of each function before composing to ensure the composition is valid for all xx.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra

Formulas

(f ∘ g)(x) = f(g(x))
f(x) = 2x + 3
g(x) = x^2

Theorems

Function Composition Theorem

Suitable Grade Level

Grades 9-11