Math Problem Statement

Find the functional values to the algebraic operations  \frac{f}{g} \binom {x} , (fg)(x), fog(x), and gof(x) by explaining the way of performing operations. Show all steps of calculations.

Solution

To find the functional values of the given operations fg(x)\frac{f}{g}(x), (fg)(x)(fg)(x), (fg)(x)(f \circ g)(x), and (gf)(x)(g \circ f)(x), we must understand the steps to compute these operations for given functions f(x)f(x) and g(x)g(x).

Let’s define f(x)f(x) and g(x)g(x) to work with specific examples:

Example Functions:

  • f(x)=2x+3f(x) = 2x + 3
  • g(x)=x21g(x) = x^2 - 1

1. Division of functions: fg(x)\frac{f}{g}(x):

This operation involves dividing f(x)f(x) by g(x)g(x): fg(x)=f(x)g(x)=2x+3x21.\frac{f}{g}(x) = \frac{f(x)}{g(x)} = \frac{2x + 3}{x^2 - 1}.

  • Compute f(x)=2x+3f(x) = 2x + 3.
  • Compute g(x)=x21g(x) = x^2 - 1.
  • Combine them as a fraction: fg(x)=2x+3x21.\frac{f}{g}(x) = \frac{2x + 3}{x^2 - 1}.

Domain Restriction: Since division by zero is undefined, we exclude values of xx where g(x)=0g(x) = 0. Solve x21=0x^2 - 1 = 0: x=±1.x = \pm 1. Therefore, the domain of fg(x)\frac{f}{g}(x) is all real numbers except x=±1x = \pm 1.

2. Product of functions: (fg)(x)(fg)(x):

This operation involves multiplying f(x)f(x) and g(x)g(x): (fg)(x)=f(x)g(x)=(2x+3)(x21).(fg)(x) = f(x) \cdot g(x) = (2x + 3)(x^2 - 1).

  • Expand the expression: (fg)(x)=(2x+3)(x21)=2x32x+3x23.(fg)(x) = (2x + 3)(x^2 - 1) = 2x^3 - 2x + 3x^2 - 3.
  • Combine like terms: (fg)(x)=2x3+3x22x3.(fg)(x) = 2x^3 + 3x^2 - 2x - 3.

3. Composition of functions: (fg)(x)(f \circ g)(x):

This operation involves substituting g(x)g(x) into f(x)f(x): (fg)(x)=f(g(x))=f(x21).(f \circ g)(x) = f(g(x)) = f(x^2 - 1).

  • Start with f(x)=2x+3f(x) = 2x + 3.
  • Replace xx in f(x)f(x) with g(x)=x21g(x) = x^2 - 1: f(g(x))=2(x21)+3.f(g(x)) = 2(x^2 - 1) + 3.
  • Simplify: f(g(x))=2x22+3=2x2+1.f(g(x)) = 2x^2 - 2 + 3 = 2x^2 + 1.

4. Composition of functions: (gf)(x)(g \circ f)(x):

This operation involves substituting f(x)f(x) into g(x)g(x): (gf)(x)=g(f(x))=g(2x+3).(g \circ f)(x) = g(f(x)) = g(2x + 3).

  • Start with g(x)=x21g(x) = x^2 - 1.
  • Replace xx in g(x)g(x) with f(x)=2x+3f(x) = 2x + 3: g(f(x))=(2x+3)21.g(f(x)) = (2x + 3)^2 - 1.
  • Expand (2x+3)2(2x + 3)^2: (2x+3)2=4x2+12x+9.(2x + 3)^2 = 4x^2 + 12x + 9.
  • Subtract 1: g(f(x))=4x2+12x+91=4x2+12x+8.g(f(x)) = 4x^2 + 12x + 9 - 1 = 4x^2 + 12x + 8.

Final Results:

  1. fg(x)=2x+3x21,  x±1\frac{f}{g}(x) = \frac{2x + 3}{x^2 - 1}, \; x \neq \pm 1.
  2. (fg)(x)=2x3+3x22x3(fg)(x) = 2x^3 + 3x^2 - 2x - 3.
  3. (fg)(x)=2x2+1(f \circ g)(x) = 2x^2 + 1.
  4. (gf)(x)=4x2+12x+8(g \circ f)(x) = 4x^2 + 12x + 8.

Would you like a graph of these functions or further clarifications?


Related Questions:

  1. What are the domains of f(x)f(x), g(x)g(x), and the resulting compositions?
  2. How would these operations differ if f(x)f(x) or g(x)g(x) had discontinuities?
  3. Can you explain the difference between fg(x)f \circ g(x) and gf(x)g \circ f(x)?
  4. What happens when g(x)g(x) is a trigonometric or exponential function?
  5. How do we interpret these operations in terms of real-world applications?

Tip:

Always check the domains of the individual functions and ensure valid substitutions or operations when dealing with composition or division of functions.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Function Operations
Composition of Functions

Formulas

Division of functions: \( \frac{f}{g}(x) = \frac{f(x)}{g(x)} \)
Product of functions: \( (fg)(x) = f(x) \cdot g(x) \)
Composition of functions: \( (f \circ g)(x) = f(g(x)) \)
Composition of functions: \( (g \circ f)(x) = g(f(x)) \)

Theorems

Domain restrictions in function operations
Properties of polynomial functions

Suitable Grade Level

Grades 10-12