Math Problem Statement

f(x)=(x-3)/(9x+4)

Solution

You have the function f(x)=x39x+4f(x) = \frac{x - 3}{9x + 4}.

Let's break down some key properties of this function:

1. Domain:

The domain of the function includes all values of xx except where the denominator is zero, since division by zero is undefined.

Set the denominator 9x+4=09x + 4 = 0 and solve for xx: 9x+4=09x=4x=499x + 4 = 0 \quad \Rightarrow \quad 9x = -4 \quad \Rightarrow \quad x = -\frac{4}{9} Therefore, the domain is: x(,49)(49,)x \in (-\infty, -\frac{4}{9}) \cup (-\frac{4}{9}, \infty)

2. Vertical Asymptote:

A vertical asymptote occurs where the denominator is zero. From the domain, we know there is a vertical asymptote at x=49x = -\frac{4}{9}.

3. Horizontal Asymptote:

For rational functions like this one, we can determine the horizontal asymptote by comparing the degrees of the numerator and denominator.

  • The degree of the numerator x3x - 3 is 1.
  • The degree of the denominator 9x+49x + 4 is also 1.

When the degrees are the same, the horizontal asymptote is the ratio of the leading coefficients. In this case: Horizontal Asymptote: y=19\text{Horizontal Asymptote: } y = \frac{1}{9}

4. Intercepts:

  • x-intercept: Set f(x)=0f(x) = 0, which happens when the numerator is zero: x3=0x=3x - 3 = 0 \quad \Rightarrow \quad x = 3 So, the x-intercept is (3,0)(3, 0).
  • y-intercept: Set x=0x = 0 and evaluate f(0)f(0): f(0)=039(0)+4=34f(0) = \frac{0 - 3}{9(0) + 4} = \frac{-3}{4} So, the y-intercept is (0,34)\left( 0, -\frac{3}{4} \right).

Would you like further clarification or additional details on any part of this explanation?

Here are 5 questions to deepen your understanding:

  1. How would the function change if the numerator were x+3x + 3?
  2. What would the domain and asymptotes be for f(x)=2x55x+1f(x) = \frac{2x - 5}{5x + 1}?
  3. How does the horizontal asymptote affect the behavior of f(x)f(x) as xx \to \infty?
  4. Can you find the inverse of this function?
  5. What happens to the function's behavior near the vertical asymptote?

Tip: Always check for points where the denominator equals zero to avoid undefined values.

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Domain
Asymptotes
Intercepts

Formulas

Vertical asymptote: Set the denominator equal to zero
Horizontal asymptote: Compare degrees of numerator and denominator
Intercepts: Solve for x and y where the function equals zero

Theorems

Rational function properties (asymptotes and intercepts)
Domain restrictions based on denominator

Suitable Grade Level

Grades 10-12