Math Problem Statement

For the functions ​f(x)equals11 minus StartFraction 132 Over x plus 11 EndFraction and ​g(x)equalsStartFraction 11 Over x EndFraction ​, find each of the following functions and state its domain. a. f plus g b. fminusg c. ftimesg d. StartFraction f Over g EndFraction e. StartFraction g Over f EndFraction Question content area bottom Part 1 a. ​(fplus​g)(x)equals

StartFraction 11 x squared plus 121 Over x left parenthesis x plus 11 right parenthesis EndFraction ​(Simplify your​ answer.) Part 2 The domain of fplusg is

left parenthesis negative infinity comma negative 11 right parenthesis union left parenthesis negative 11 comma 0 right parenthesis union left parenthesis 0 comma. ​(Type your answer in interval​ notation.)

Solution

Let’s go through each of the functions and compute their operations step by step, along with determining their domain.

Part 1: (f + g)(x)

Given:

  • f(x)=11132x+11f(x) = 11 - \frac{132}{x + 11}
  • g(x)=11xg(x) = \frac{11}{x}

To compute (f+g)(x)=f(x)+g(x)(f + g)(x) = f(x) + g(x), we first write it as a single fraction:

(f+g)(x)=(11132x+11)+11x(f + g)(x) = \left( 11 - \frac{132}{x + 11} \right) + \frac{11}{x}

Now, let's combine these two terms into a single fraction. To do that, we need a common denominator. The denominators are (x+11)(x + 11) and xx, so the common denominator is x(x+11)x(x + 11). Let’s rewrite each term with this common denominator:

f(x)=11132x+11=11x(x+11)x(x+11)132x+11=11x2+121xx(x+11)132x+11f(x) = 11 - \frac{132}{x + 11} = \frac{11x(x + 11)}{x(x + 11)} - \frac{132}{x + 11} = \frac{11x^2 + 121x}{x(x + 11)} - \frac{132}{x + 11} g(x)=11x=11(x+11)x(x+11)g(x) = \frac{11}{x} = \frac{11(x + 11)}{x(x + 11)}

Now, add the two fractions:

(f+g)(x)=11x2+121x132+11(x+11)x(x+11)(f + g)(x) = \frac{11x^2 + 121x - 132 + 11(x + 11)}{x(x + 11)}

Simplify the numerator:

11x2+121x132+11x+121=11x2+132x1111x^2 + 121x - 132 + 11x + 121 = 11x^2 + 132x - 11

So, we get:

(f+g)(x)=11x2+132x11x(x+11)(f + g)(x) = \frac{11x^2 + 132x - 11}{x(x + 11)}

Thus, the simplified expression for (f+g)(x)(f + g)(x) is:

(f+g)(x)=11x2+132x11x(x+11)(f + g)(x) = \frac{11x^2 + 132x - 11}{x(x + 11)}

Part 2: Domain of (f+g)(x)(f + g)(x)

To determine the domain of (f+g)(x)(f + g)(x), we must find the values of xx where the expression is undefined. The expression is undefined when either of the denominators xx or x+11x + 11 equals zero.

  • x=0x = 0 makes the denominator zero.
  • x=11x = -11 makes the denominator zero.

Therefore, the domain is all real numbers except x=0x = 0 and x=11x = -11, which in interval notation is:

(,11)(11,0)(0,)(-\infty, -11) \cup (-11, 0) \cup (0, \infty)

Summary:

  • (f + g)(x) is 11x2+132x11x(x+11)\frac{11x^2 + 132x - 11}{x(x + 11)}
  • The domain of (f+g)(x)(f + g)(x) is (,11)(11,0)(0,)(-\infty, -11) \cup (-11, 0) \cup (0, \infty).

Would you like further details on any part of this solution or help with parts b, c, d, and e? Here are a few questions that might interest you:

  1. How do we find the domain of a function with multiple terms?
  2. What happens if we try to evaluate f(x)f(x) and g(x)g(x) at x=11x = -11 or x=0x = 0?
  3. How would you simplify similar expressions for other functions?
  4. How do operations like addition, subtraction, multiplication, and division affect the domain?
  5. What are some common techniques for combining rational functions?

Tip: When combining rational functions, always check for common denominators and simplify the result wherever possible.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Domain of Functions
Operations on Functions

Formulas

f(x) = 11 - (132 / (x + 11))
g(x) = (11 / 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(x) / g(x)

Theorems

Domain of Rational Functions
Domain of Sum and Difference of Functions
Domain of Product and Quotient of Functions

Suitable Grade Level

Grades 9-11