Math Problem Statement

Find f + g, f - g, f * g, and f / g for f(x) = √(4x - 1) and g(x) = 1/x, and determine the domain of each.

Solution

This example focuses on finding the sum f+gf + g, difference fgf - g, product fgf \cdot g, and quotient fg\frac{f}{g} of two functions f(x)=4x1f(x) = \sqrt{4x - 1} and g(x)=1xg(x) = \frac{1}{x}, along with determining the domain of each resulting function. Let’s go over each part and how the domain is derived:

  1. Sum f+gf + g: f+g=4x1+1xf + g = \sqrt{4x - 1} + \frac{1}{x}

    • Domain: The domain of f(x)=4x1f(x) = \sqrt{4x - 1} is x14x \geq \frac{1}{4} because 4x104x - 1 \geq 0 (ensuring the radicand is non-negative).
    • The domain of g(x)=1xg(x) = \frac{1}{x} is x0x \neq 0.
    • Combining these, the domain is [14,)\left[\frac{1}{4}, \infty\right).
  2. Difference fgf - g: fg=4x11xf - g = \sqrt{4x - 1} - \frac{1}{x}

    • Domain: Similar reasoning as with f+gf + g, so the domain remains [14,)\left[\frac{1}{4}, \infty\right).
  3. Product fgf \cdot g: fg=4x1xf \cdot g = \frac{\sqrt{4x - 1}}{x}

    • Domain: Since both f(x)f(x) and g(x)g(x) must be defined, the domain is [14,)\left[\frac{1}{4}, \infty\right).
  4. Quotient fg\frac{f}{g}: fg=x4x1\frac{f}{g} = x \sqrt{4x - 1}

    • Domain: We avoid division by zero from g(x)g(x), resulting in the domain [14,)\left[\frac{1}{4}, \infty\right).

Each operation maintains the initial restrictions on xx from both f(x)f(x) and g(x)g(x), ensuring the function outputs are real numbers.

Would you like more details on how these functions are combined or on the domain restrictions?

Related Questions

  1. What would happen to the domains if g(x)g(x) were a different function?
  2. How would the process change if f(x)f(x) involved a different root, like 4x13\sqrt[3]{4x - 1}?
  3. What are some techniques for combining functions with complex expressions?
  4. How would we find the range of each combined function in addition to the domain?
  5. How do we interpret and visualize the domain on a number line or graph?

Tip:

When determining the domain of a combined function, always consider both functions' individual restrictions.

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Math Problem Analysis

Mathematical Concepts

Function operations
Domain of functions
Square roots
Rational functions

Formulas

f + g = √(4x - 1) + 1/x
f - g = √(4x - 1) - 1/x
f * g = (√(4x - 1)) / x
f / g = x * √(4x - 1)

Theorems

Domain restriction for square root functions
Domain restriction for rational functions

Suitable Grade Level

Grades 11-12