Math Problem Statement

B. Consider the following rational functions. Construct a table of values where x = - 2 -1, 0, 1, 2.

  1. f(x) = 2/(x + 1)

  2. f(x) = (3x)/(x + 3)

Solution

Let's create the tables of values for the given rational functions.

1. f(x)=2x+1f(x) = \frac{2}{x + 1}

We will substitute x=2,1,0,1,2x = -2, -1, 0, 1, 2 into the function:

xxf(x)=2x+1f(x) = \frac{2}{x + 1}
-2f(2)=22+1=21=2f(-2) = \frac{2}{-2 + 1} = \frac{2}{-1} = -2
-1f(1)=21+1=20f(-1) = \frac{2}{-1 + 1} = \frac{2}{0} (undefined)
0f(0)=20+1=21=2f(0) = \frac{2}{0 + 1} = \frac{2}{1} = 2
1f(1)=21+1=22=1f(1) = \frac{2}{1 + 1} = \frac{2}{2} = 1
2f(2)=22+1=230.67f(2) = \frac{2}{2 + 1} = \frac{2}{3} \approx 0.67

Notice that at x=1x = -1, the function is undefined because the denominator becomes zero.

2. f(x)=3xx+3f(x) = \frac{3x}{x + 3}

Now, we substitute the same xx-values into the second function:

xxf(x)=3xx+3f(x) = \frac{3x}{x + 3}
-2f(2)=3(2)2+3=61=6f(-2) = \frac{3(-2)}{-2 + 3} = \frac{-6}{1} = -6
-1f(1)=3(1)1+3=32=1.5f(-1) = \frac{3(-1)}{-1 + 3} = \frac{-3}{2} = -1.5
0f(0)=3(0)0+3=03=0f(0) = \frac{3(0)}{0 + 3} = \frac{0}{3} = 0
1f(1)=3(1)1+3=34=0.75f(1) = \frac{3(1)}{1 + 3} = \frac{3}{4} = 0.75
2f(2)=3(2)2+3=65=1.2f(2) = \frac{3(2)}{2 + 3} = \frac{6}{5} = 1.2

Summary:

  1. For f(x)=2x+1f(x) = \frac{2}{x + 1}, the function is undefined at x=1x = -1, and the other values are straightforward.
  2. For f(x)=3xx+3f(x) = \frac{3x}{x + 3}, the function is continuous, with various values for xx.

Let me know if you want more details or have questions.

Here are some questions that might expand your understanding:

  1. How does the behavior of each function change as xx \to -\infty?
  2. What happens to each function as xx \to \infty?
  3. Can you determine the asymptotes of each function?
  4. How would you sketch the graph of each function?
  5. What does the undefined point at x=1x = -1 in the first function signify?

Tip: Rational functions often have vertical asymptotes where the denominator becomes zero. Identifying these can help you better understand their behavior.

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Function Evaluation
Algebra

Formulas

f(x) = 2/(x + 1)
f(x) = (3x)/(x + 3)

Theorems

Properties of Rational Functions
Behavior of Functions at Undefined Points
Asymptotes

Suitable Grade Level

Grades 9-11