Math Problem Statement

Let f(x) = x^2 and g(x) = √(16 - x) - 2. Find (f/g)(x) and state its domain in interval notation.

Solution

Let's analyze the problem provided in the image.

Problem Statement

We are given two functions:

  • f(x)=x2f(x) = x^2
  • g(x)=16x2g(x) = \sqrt{16 - x} - 2

We are asked to find the composite function (fg)(x)\left(\frac{f}{g}\right)(x) and state its domain in interval notation.

Solution

Step 1: Determine the Composite Function (fg)(x)\left(\frac{f}{g}\right)(x)

The composite function (fg)(x)\left(\frac{f}{g}\right)(x) is defined as: (fg)(x)=f(x)g(x)\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} Substituting the given functions f(x)f(x) and g(x)g(x): (fg)(x)=x216x2\left(\frac{f}{g}\right)(x) = \frac{x^2}{\sqrt{16 - x} - 2}

Step 2: Determine the Domain

The domain of the function (fg)(x)\left(\frac{f}{g}\right)(x) is determined by the following conditions:

  1. The denominator g(x)g(x) must not be zero: g(x)=16x20g(x) = \sqrt{16 - x} - 2 \neq 0 Solving 16x=2\sqrt{16 - x} = 2: 16x=2    16x=4    x=12\sqrt{16 - x} = 2 \implies 16 - x = 4 \implies x = 12 Therefore, x12x \neq 12.

  2. The expression under the square root in g(x)g(x) must be non-negative: 16x0    x1616 - x \geq 0 \implies x \leq 16 This gives xx must be in the interval (,16](-\infty, 16].

Combining these two conditions, the domain is: (,12)(12,16](-\infty, 12) \cup (12, 16]

Final Answer

The composite function (fg)(x)=x216x2\left(\frac{f}{g}\right)(x) = \frac{x^2}{\sqrt{16 - x} - 2} has the domain (,12)(12,16](-\infty, 12) \cup (12, 16].


Would you like more details or have any questions about this solution?

Here are five related questions to explore further:

  1. How would the domain change if f(x)f(x) was x3x^3 instead of x2x^2?
  2. Can you find the domain of g(x)=16x2g(x) = \sqrt{16 - x} - 2 alone?
  3. How does the behavior of (fg)(x)\left(\frac{f}{g}\right)(x) change near x=12x = 12?
  4. What would happen to the domain if the square root in g(x)g(x) was replaced with a cube root?
  5. How do you determine the domain of a function involving logarithms?

Tip: Always check the conditions under which the denominator of a fraction and the expression under a square root are valid to ensure the correct domain is determined.

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Math Problem Analysis

Mathematical Concepts

Function Operations
Domain and Range
Square Roots
Rational Functions

Formulas

(f/g)(x) = f(x) / g(x)
Domain conditions for square roots and rational functions

Theorems

Domain restrictions: Denominator not equal to zero and square root of a non-negative number

Suitable Grade Level

Grades 10-12