Math Problem Statement

Find any asymptotes and holes in the graph of the rational function: f(x) = (x^2 + 2x + 1) / (4x^2 - x - 5).

Solution

To find the vertical asymptotes, horizontal asymptotes, and holes for the given rational function:

f(x)=x2+2x+14x2x5f(x) = \frac{x^2 + 2x + 1}{4x^2 - x - 5}

let’s analyze each aspect:

1. Vertical Asymptotes

Vertical asymptotes occur where the denominator is zero, provided that the numerator is not zero at those points.

Step:

Solve 4x2x5=04x^2 - x - 5 = 0.

Using the quadratic formula: x=(1)±(1)244(5)24x = \frac{-(-1) \pm \sqrt{(-1)^2 - 4 \cdot 4 \cdot (-5)}}{2 \cdot 4} x=1±1+808x = \frac{1 \pm \sqrt{1 + 80}}{8} x=1±818x = \frac{1 \pm \sqrt{81}}{8} x=1±98x = \frac{1 \pm 9}{8}

This gives: x=108=54andx=88=1x = \frac{10}{8} = \frac{5}{4} \quad \text{and} \quad x = \frac{-8}{8} = -1

So, the vertical asymptotes are at x=54x = \frac{5}{4} and x=1x = -1, unless these points are also zeros of the numerator (which would make them holes).

2. Horizontal Asymptotes

Horizontal asymptotes are determined by comparing the degrees of the numerator and denominator.

  • The numerator (x2+2x+1x^2 + 2x + 1) and the denominator (4x2x54x^2 - x - 5) are both degree 2.
  • For functions where the degrees are the same, the horizontal asymptote is given by the ratio of the leading coefficients.

Thus: y=14y = \frac{1}{4}

3. Holes

To find holes, check if any factors cancel between the numerator and the denominator.

Factor the numerator: x2+2x+1=(x+1)2x^2 + 2x + 1 = (x + 1)^2

And the denominator: 4x2x5=(4x+5)(x1)4x^2 - x - 5 = (4x + 5)(x - 1)

Since no factors cancel between the numerator and the denominator, there are no holes.

Summary:

  • Vertical Asymptotes: x=54,x=1x = \frac{5}{4}, x = -1
  • Horizontal Asymptote: y=14y = \frac{1}{4}
  • Holes: None (DNE)

Would you like more detailed explanations or have any questions?


Related Questions:

  1. How do you find slant asymptotes for rational functions?
  2. What if both numerator and denominator had a common factor?
  3. Can a rational function have both vertical and horizontal asymptotes?
  4. How are holes different from vertical asymptotes?
  5. How can asymptotes be determined using limits?

Tip:

For functions with the same degree in numerator and denominator, remember that the horizontal asymptote is the ratio of leading coefficients.

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Asymptotes
Holes in Graphs

Formulas

Quadratic Formula: x = [-b ± sqrt(b^2 - 4ac)] / 2a
Horizontal Asymptote: if degrees of numerator and denominator are the same, y = leading coefficient of numerator / leading coefficient of denominator

Theorems

Asymptote Rules
Hole Identification in Rational Functions

Suitable Grade Level

Grades 10-12