To graph the rational function \( f(x) = \frac{x + 2}{x^2 + x - 20} \), we will follow the seven step strategy as outlined.
Part 1: Determine Symmetry
- Symmetry:
- y-axis symmetry: \( f(-x) = f(x) \)
- origin symmetry: \( f(-x) = -f(x) \)
- For our function: \[ f(-x) = \frac{-x + 2}{(-x)^2 + (-x) - 20} = \frac{-x + 2}{x^2 - x - 20} \] This is not equal to \( f(x) \) nor is it equal to \( -f(x) \). Therefore, this function has neither y-axis symmetry nor origin symmetry.
Conclusion:
Neither y-axis symmetry nor origin symmetry
Part 2: Find the y-intercept and x-intercept
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Y-intercept:
- To find the y-intercept, set \( x = 0 \): \[ f(0) = \frac{0 + 2}{0^2 + 0 - 20} = \frac{2}{-20} = -\frac{1}{10} \]
- Thus, the y-intercept is \( -\frac{1}{10} \).
-
X-intercept:
- To find the x-intercept, set \( f(x) = 0 \):
- \( \frac{x + 2}{x^2 + x - 20} = 0 \) implies \( x + 2 = 0 \) or \( x = -2 \).
- Thus, the x-intercept is \( -2 \).
Conclusion:
A. The y-intercept is \( -\frac{1}{10} \).
A. The x-intercept is \( -2 \).
Part 3: Find the vertical and horizontal asymptotes
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Vertical Asymptotes:
- Vertical asymptotes occur where the denominator is zero, provided that these points do not cancel with the numerator.
- Factor the denominator: \[ x^2 + x - 20 = (x - 4)(x + 5) \]
- Set the denominator to zero: \[ (x - 4)(x + 5) = 0 \Rightarrow x - 4 = 0 \rightarrow x = 4 \] \[ x + 5 = 0 \Rightarrow x = -5 \]
- Thus, the vertical asymptotes are \( x = 4 \) and \( x = -5 \).
-
Horizontal Asymptotes:
- For rational functions where the degree of the numerator is less than the degree of the denominator, the horizontal asymptote is \( y = 0 \).
- The degrees are:
- Degree of numerator: 1
- Degree of denominator: 2
- Thus, the horizontal asymptote is \( y = 0 \).
Conclusion:
A. The equations of the vertical asymptotes are \(x = 4, x = -5\).
A. The horizontal asymptote is \(y = 0\).
With this information, you can proceed to graph the rational function.