Math Problem Statement

give me full solution and find the domain if needed

Perform the following fundamental operations on the given functions f(x) = √(x-2) and g(x) = 1/x. Then, determine the domain of each operation.

Solution

Let's solve the problem by performing the operations step-by-step and finding the domains for each case.

Given functions:

  • f(x)=x2f(x) = \sqrt{x - 2}
  • g(x)=1xg(x) = \frac{1}{x}

We are required to perform various operations and determine the domain for each.

a. (f+g)(x)=f(x)+g(x)(f + g)(x) = f(x) + g(x)

(f+g)(x)=x2+1x(f + g)(x) = \sqrt{x - 2} + \frac{1}{x}

Domain:

  • For x2\sqrt{x - 2}, we need x20x2x - 2 \geq 0 \Rightarrow x \geq 2.
  • For 1x\frac{1}{x}, x0x \neq 0.

Thus, the domain is x2x \geq 2 and x0x \neq 0. Therefore, the domain is x[2,){0}x \in [2, \infty) \setminus \{0\}.

b. (fg)(x)=f(x)g(x)(f - g)(x) = f(x) - g(x)

(fg)(x)=x21x(f - g)(x) = \sqrt{x - 2} - \frac{1}{x}

Domain:

The domain is the same as part (a), x[2,){0}x \in [2, \infty) \setminus \{0\}.

c. (fg)(x)=f(x)g(x)(f \cdot g)(x) = f(x) \cdot g(x)

(fg)(x)=x21x=x2x(f \cdot g)(x) = \sqrt{x - 2} \cdot \frac{1}{x} = \frac{\sqrt{x - 2}}{x}

Domain:

The same restrictions apply as before:

  • x2x \geq 2
  • x0x \neq 0

Thus, the domain is x[2,){0}x \in [2, \infty) \setminus \{0\}.

d. (fg)(x)=f(x)g(x)\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)}

(fg)(x)=x21x=xx2\left(\frac{f}{g}\right)(x) = \frac{\sqrt{x - 2}}{\frac{1}{x}} = x \sqrt{x - 2}

Domain:

The same restrictions apply:

  • x2x \geq 2
  • x0x \neq 0

Thus, the domain is x[2,){0}x \in [2, \infty) \setminus \{0\}.

e. (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x))

(fg)(x)=f(1x)=1x2(f \circ g)(x) = f\left(\frac{1}{x}\right) = \sqrt{\frac{1}{x} - 2}

Domain:

For f(g(x))f(g(x)) to be defined, 1x20\frac{1}{x} - 2 \geq 0.

1x2x12\frac{1}{x} \geq 2 \Rightarrow x \leq \frac{1}{2}

Also, x0x \neq 0. Thus, the domain is x(,0)(0,12]x \in (-\infty, 0) \cup (0, \frac{1}{2}].

f. (gf)(x)=g(f(x))(g \circ f)(x) = g(f(x))

(gf)(x)=g(x2)=1x2(g \circ f)(x) = g\left(\sqrt{x - 2}\right) = \frac{1}{\sqrt{x - 2}}

Domain:

For x2\sqrt{x - 2} to be defined, we need x2x \geq 2. Also, x20\sqrt{x - 2} \neq 0, which means x2x \neq 2.

Thus, the domain is x(2,)x \in (2, \infty).

g. (ff)(x)=f(f(x))(f \circ f)(x) = f(f(x))

(ff)(x)=f(x2)=x22(f \circ f)(x) = f\left(\sqrt{x - 2}\right) = \sqrt{\sqrt{x - 2} - 2}

Domain:

For the expression to be valid:

  • x220\sqrt{x - 2} - 2 \geq 0 [ \sqrt{x - 2} \geq 2 \Rightarrow x - 2 \ge

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Math Problem Analysis

Mathematical Concepts

Functions
Operations on Functions
Domain and Range

Formulas

(f + g)(x) = f(x) + g(x)
(f - g)(x) = f(x) - g(x)
(f ⋅ g)(x) = f(x) ⋅ g(x)
(f / g)(x) = f(x) / g(x)
(f ∘ g)(x) = f(g(x))

Theorems

Function Composition
Domain Restrictions for Square Roots and Rational Functions

Suitable Grade Level

Grades 10-12