Math Problem Statement

Find f + g, f - g, fg, and f/g. Determine the domain for each function where f(x) = √(x - 1) and g(x) = √(x - 2).

Solution

Let's break down this problem step by step:

We are given two functions:

  • f(x)=x1f(x) = \sqrt{x - 1}
  • g(x)=x2g(x) = \sqrt{x - 2}

1. Domain of f(x)f(x) and g(x)g(x):

For the square root functions, the expressions under the square root must be non-negative.

  • For f(x)=x1f(x) = \sqrt{x - 1}, we need x10x - 1 \geq 0, so x1x \geq 1. Therefore, the domain of f(x)f(x) is [1,)[1, \infty).

  • For g(x)=x2g(x) = \sqrt{x - 2}, we need x20x - 2 \geq 0, so x2x \geq 2. Therefore, the domain of g(x)g(x) is [2,)[2, \infty).

2. Operations on ff and gg:

We now find the domain for the following operations: f+gf + g, fgf - g, fgf \cdot g, and fg\frac{f}{g}.

  • For f+gf + g and fgf - g:

    The domain will be the intersection of the domains of f(x)f(x) and g(x)g(x), which is [2,)[2, \infty).

  • For fgf \cdot g:

    The domain is also the intersection of [1,)[1, \infty) and [2,)[2, \infty), which is [2,)[2, \infty).

  • For fg\frac{f}{g}:

    The domain is [2,)[2, \infty), but we must exclude any points where g(x)=0g(x) = 0 because division by zero is undefined. However, g(x)=x2g(x) = \sqrt{x - 2} is only zero when x=2x = 2. So, the domain of fg\frac{f}{g} is (2,)(2, \infty).

Final answer:

  • The domain of f+gf + g, fgf - g, and fgf \cdot g is [2,)[2, \infty).
  • The domain of fg\frac{f}{g} is (2,)(2, \infty).

It looks like the answer marked in the image (for fg\frac{f}{g}) is correct: (2,)(2, \infty).

Would you like more details or have any further questions?

5 Related Questions:

  1. How do you find the domain of a square root function?
  2. Why does g(x)=x2g(x) = \sqrt{x - 2} impact the domain of fg\frac{f}{g}?
  3. What happens if g(x)=0g(x) = 0 when dividing functions?
  4. Can domains of different types of functions overlap in more complex cases?
  5. How would the domain change if f(x)f(x) or g(x)g(x) included additional terms (like a polynomial)?

Tip: Always check for division by zero when determining the domain of rational functions!

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Math Problem Analysis

Mathematical Concepts

Functions
Domain of a function
Square root function
Intersection of domains
Division of functions

Formulas

√(x - a) ≥ 0 implies x ≥ a
Intersection of domains: A ∩ B
Division by zero is undefined

Theorems

Square Root Function Domain
Intersection of Sets for Domain Determination
Domain Exclusion for Division by Zero

Suitable Grade Level

Grades 10-12