Math Problem Statement

Find f + g, f - g, fg, and f / g. Determine the domain for each function. f(x) = √x ; g(x) = x - 17.

Solution

We are given the following functions and asked to find:

  • f+gf + g
  • fgf - g
  • fgfg
  • fg\frac{f}{g}

The functions are:

  • f(x)=xf(x) = \sqrt{x}
  • g(x)=x17g(x) = x - 17

We'll also determine the domain of each resulting function.

1. f+gf + g

(f+g)(x)=f(x)+g(x)=x+(x17)(f + g)(x) = f(x) + g(x) = \sqrt{x} + (x - 17) Domain:

  • f(x)=xf(x) = \sqrt{x} requires x0x \geq 0 because we cannot take the square root of a negative number.
  • g(x)=x17g(x) = x - 17 is defined for all real numbers.

Thus, the domain of f+gf + g is [0,)[0, \infty).

2. fgf - g

(fg)(x)=f(x)g(x)=x(x17)=xx+17(f - g)(x) = f(x) - g(x) = \sqrt{x} - (x - 17) = \sqrt{x} - x + 17 Domain:

  • Same as f(x)f(x), x0x \geq 0.

Thus, the domain of fgf - g is [0,)[0, \infty).

3. fgfg

(fg)(x)=f(x)g(x)=x(x17)=x(x17)(fg)(x) = f(x) \cdot g(x) = \sqrt{x} \cdot (x - 17) = \sqrt{x}(x - 17) Domain:

  • Again, the square root function x\sqrt{x} requires x0x \geq 0.

Thus, the domain of fgfg is [0,)[0, \infty).

4. fg\frac{f}{g}

(fg)(x)=xx17\left(\frac{f}{g}\right)(x) = \frac{\sqrt{x}}{x - 17} Domain:

  • f(x)=xf(x) = \sqrt{x} requires x0x \geq 0.
  • The denominator g(x)=x170g(x) = x - 17 \neq 0, so x17x \neq 17.

Thus, the domain of fg\frac{f}{g} is [0,){17}[0, \infty) \setminus \{17\}, meaning x0x \geq 0 but x17x \neq 17.

Summary:

  • f+g=x+x17f + g = \sqrt{x} + x - 17, domain: [0,)[0, \infty)
  • fg=xx+17f - g = \sqrt{x} - x + 17, domain: [0,)[0, \infty)
  • fg=x(x17)fg = \sqrt{x}(x - 17), domain: [0,)[0, \infty)
  • fg=xx17\frac{f}{g} = \frac{\sqrt{x}}{x - 17}, domain: [0,){17}[0, \infty) \setminus \{17\}

Would you like more details or have any further questions?
Here are some related questions:

  1. What is the difference between the domain and range of a function?
  2. How can you determine if a function is continuous or discontinuous?
  3. How do we handle square root functions when combined with other operations?
  4. Can you explain how division affects the domain of a function?
  5. How would you graph these combined functions to visualize their domains?

Tip: When dealing with square roots, always ensure the expression under the root is non-negative to determine the function's domain.

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Math Problem Analysis

Mathematical Concepts

Function Operations
Square Root Functions
Domain of Functions

Formulas

(f + g)(x) = f(x) + g(x)
(f - g)(x) = f(x) - g(x)
(fg)(x) = f(x) * g(x)
(f / g)(x) = f(x) / g(x)

Theorems

The square root function requires that the argument be non-negative.
Division by zero is undefined, so the denominator must not be zero.

Suitable Grade Level

Grades 9-11