Questions: The functions f and g are defined as f(x)=x-5, g(x)=√(x+6). a) Find the domain of f, g, f+g, f-g, fg, ff, f/g, and g/f. b) Find (f+g)(x), (f-g)(x), (fg)(x), (f)(x),(f/g)(x), and (g/f)(x). a) The domain of f is (-∞, ∞). (Type your answer in interval notation.) The domain of g is . (Type your answer in interval notation.)

The functions f and g are defined as f(x)=x-5, g(x)=√(x+6).
a) Find the domain of f, g, f+g, f-g, fg, ff, f/g, and g/f.
b) Find (f+g)(x), (f-g)(x), (fg)(x), (f)(x),(f/g)(x), and (g/f)(x).
a) The domain of f is (-∞, ∞).
(Type your answer in interval notation.)
The domain of g is .
(Type your answer in interval notation.)
Transcript text: The functions $f$ and $g$ are defined as $f(x)=x-5, g(x)=\sqrt{x+6}$. a) Find the domain of $f, g, f+g, f-g, f g, f f, \frac{f}{g}$, and $\frac{g}{f}$. b) Find $(f+g)(x)$, $(f-g)(x)$, $(f g)(x)$, $(f)(x),\left(\frac{f}{g}\right)(x)$, and $\left(\frac{g}{f}\right)(x)$. a) The domain of $f$ is $(-\infty, \infty)$. (Type your answer in interval notation.) The domain of $g$ is $\square$ . (Type your answer in interval notation.)
failed

Solution

failed
failed

Solution Steps

To solve the given problem, we need to determine the domains of the functions f f and g g , as well as their combinations. Then, we will find the expressions for the combined functions.

Part (a)
  1. Domain of f(x)=x5 f(x) = x - 5 : Since f(x) f(x) is a linear function, its domain is all real numbers, (,) (-\infty, \infty) .
  2. Domain of g(x)=x+6 g(x) = \sqrt{x + 6} : The expression inside the square root must be non-negative, so x+60 x + 6 \geq 0 . Therefore, the domain is [6,) [-6, \infty) .

For the combined functions:

  • f+g f + g : The domain is the intersection of the domains of f f and g g , which is [6,) [-6, \infty) .
  • fg f - g : The domain is the same as f+g f + g , which is [6,) [-6, \infty) .
  • fg f \cdot g : The domain is the same as f+g f + g , which is [6,) [-6, \infty) .
  • fg \frac{f}{g} : The domain is [6,) [-6, \infty) excluding points where g(x)=0 g(x) = 0 . Since g(x)=x+6 g(x) = \sqrt{x + 6} , g(x)=0 g(x) = 0 when x=6 x = -6 . Thus, the domain is (6,) (-6, \infty) .
  • gf \frac{g}{f} : The domain is [6,) [-6, \infty) excluding points where f(x)=0 f(x) = 0 . Since f(x)=x5 f(x) = x - 5 , f(x)=0 f(x) = 0 when x=5 x = 5 . Thus, the domain is [6,5)(5,) [-6, 5) \cup (5, \infty) .
Part (b)
  1. (f+g)(x) (f + g)(x) : This is f(x)+g(x) f(x) + g(x) .
  2. (fg)(x) (f - g)(x) : This is f(x)g(x) f(x) - g(x) .
  3. (fg)(x) (f \cdot g)(x) : This is f(x)g(x) f(x) \cdot g(x) .
  4. (fg)(x) \left(\frac{f}{g}\right)(x) : This is f(x)g(x) \frac{f(x)}{g(x)} .
  5. (gf)(x) \left(\frac{g}{f}\right)(x) : This is g(x)f(x) \frac{g(x)}{f(x)} .
Step 1: Determine the Domain of f(x) f(x)

The function f(x)=x5 f(x) = x - 5 is a linear function. Linear functions are defined for all real numbers.

Domain of f:(,) \text{Domain of } f: (-\infty, \infty)

Step 2: Determine the Domain of g(x) g(x)

The function g(x)=x+6 g(x) = \sqrt{x + 6} is defined when the expression inside the square root is non-negative.

x+60    x6 x + 6 \geq 0 \implies x \geq -6

Domain of g:[6,) \text{Domain of } g: [-6, \infty)

Step 3: Determine the Domain of Combined Functions
  • f+g f + g : The domain is the intersection of the domains of f f and g g .

Domain of f+g:[6,) \text{Domain of } f + g: [-6, \infty)

  • fg f - g : The domain is the same as f+g f + g .

Domain of fg:[6,) \text{Domain of } f - g: [-6, \infty)

  • fg f \cdot g : The domain is the same as f+g f + g .

Domain of fg:[6,) \text{Domain of } f \cdot g: [-6, \infty)

  • fg \frac{f}{g} : The domain is [6,) [-6, \infty) excluding points where g(x)=0 g(x) = 0 . Since g(x)=x+6 g(x) = \sqrt{x + 6} , g(x)=0 g(x) = 0 when x=6 x = -6 .

Domain of fg:(6,) \text{Domain of } \frac{f}{g}: (-6, \infty)

  • gf \frac{g}{f} : The domain is [6,) [-6, \infty) excluding points where f(x)=0 f(x) = 0 . Since f(x)=x5 f(x) = x - 5 , f(x)=0 f(x) = 0 when x=5 x = 5 .

Domain of gf:[6,5)(5,) \text{Domain of } \frac{g}{f}: [-6, 5) \cup (5, \infty)

Step 4: Find the Expressions for Combined Functions
  • (f+g)(x) (f + g)(x) :

(f+g)(x)=f(x)+g(x)=x5+x+6 (f + g)(x) = f(x) + g(x) = x - 5 + \sqrt{x + 6}

  • (fg)(x) (f - g)(x) :

(fg)(x)=f(x)g(x)=x5x+6 (f - g)(x) = f(x) - g(x) = x - 5 - \sqrt{x + 6}

  • (fg)(x) (f \cdot g)(x) :

(fg)(x)=f(x)g(x)=(x5)x+6 (f \cdot g)(x) = f(x) \cdot g(x) = (x - 5) \sqrt{x + 6}

  • (fg)(x) \left(\frac{f}{g}\right)(x) :

(fg)(x)=f(x)g(x)=x5x+6 \left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} = \frac{x - 5}{\sqrt{x + 6}}

  • (gf)(x) \left(\frac{g}{f}\right)(x) :

(gf)(x)=g(x)f(x)=x+6x5 \left(\frac{g}{f}\right)(x) = \frac{g(x)}{f(x)} = \frac{\sqrt{x + 6}}{x - 5}

Final Answer

[6,) \boxed{[-6, \infty)}

Was this solution helpful?
failed
Unhelpful
failed
Helpful