Math Problem Statement

Suppose that the functions f and g are defined as follows: f(x) = 3/x and g(x) = x - 2. Find (f/g)(x). Then, give its domain using an interval or union of intervals.

Solution

To solve the problem, let's go through the steps one by one.

Given:

  • f(x)=3xf(x) = \frac{3}{x}
  • g(x)=x2g(x) = x - 2

We are asked to find (fg)(x)\left( \frac{f}{g} \right)(x) and determine its domain.

Step 1: Find (fg)(x)\left( \frac{f}{g} \right)(x)

The expression fg\frac{f}{g} represents the function f(x)g(x)\frac{f(x)}{g(x)}.

So, (fg)(x)=f(x)g(x)=3xx2=3x(x2)\left( \frac{f}{g} \right)(x) = \frac{f(x)}{g(x)} = \frac{\frac{3}{x}}{x - 2} = \frac{3}{x(x - 2)}

Step 2: Determine the Domain

The domain of (fg)(x)\left( \frac{f}{g} \right)(x) is restricted by values of xx that would make the denominator zero.

  1. x0x \neq 0, because f(x)=3xf(x) = \frac{3}{x} would be undefined.
  2. x2x \neq 2, because g(x)=x2g(x) = x - 2 would be zero.

Thus, the domain of (fg)(x)\left( \frac{f}{g} \right)(x) is: (,0)(0,2)(2,)(-\infty, 0) \cup (0, 2) \cup (2, \infty)

Final Answer

  • Function: (fg)(x)=3x(x2)\left( \frac{f}{g} \right)(x) = \frac{3}{x(x - 2)}
  • Domain: (,0)(0,2)(2,)(-\infty, 0) \cup (0, 2) \cup (2, \infty)

Would you like a further breakdown or details on any part of the solution?


  1. How to evaluate the quotient of two functions?
  2. What steps are necessary to determine the domain of a rational function?
  3. Why do we exclude certain values from the domain?
  4. How do you simplify complex fractions like this one?
  5. What other examples involve combining functions with restricted domains?

Tip: When finding the domain of a function, always check for values that cause division by zero or negative square roots, as these restrict possible inputs.

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Math Problem Analysis

Mathematical Concepts

Function Division
Domain of Rational Functions

Formulas

f/g = f(x) / g(x)

Theorems

Domain of Rational Functions

Suitable Grade Level

Grades 10-12