How many asymptotes does the function LaTeX: f\left(x\right)=\frac{x^2-x-6}{x^2-5x-6} have?

1 answer

To determine the number of asymptotes for the function

\[ f(x) = \frac{x^2 - x - 6}{x^2 - 5x - 6}, \]

we need to investigate both vertical and horizontal asymptotes.

Step 1: Find Vertical Asymptotes

Vertical asymptotes occur where the function is undefined, which is where the denominator is equal to zero. We need to factor the denominator:

The denominator is

\[ x^2 - 5x - 6. \]

To factor it, we find two numbers that multiply to \(-6\) (the constant term) and add up to \(-5\) (the coefficient of \(x\)). These numbers are \(-6\) and \(1\). Thus, the factorization is:

\[ x^2 - 5x - 6 = (x - 6)(x + 1). \]

Setting the denominator to zero, we solve:

\[ (x - 6)(x + 1) = 0. \]

This gives us the vertical asymptotes:

\[ x - 6 = 0 \quad \Rightarrow \quad x = 6, \] \[ x + 1 = 0 \quad \Rightarrow \quad x = -1. \]

Step 2: Find Horizontal Asymptotes

To find horizontal asymptotes, we analyze the degrees of the polynomial in the numerator and the denominator.

The degrees of both the numerator and the denominator are 2 (the leading term of both is \(x^2\)). When the degrees are equal, the horizontal asymptote can be found by taking the ratio of the leading coefficients.

The leading coefficient of the numerator \(x^2 - x - 6\) is \(1\) and the leading coefficient of the denominator \(x^2 - 5x - 6\) is also \(1\). Thus, the horizontal asymptote is:

\[ y = \frac{1}{1} = 1. \]

Summary

We have found:

  • Vertical asymptotes at \(x = 6\) and \(x = -1\) (2 vertical asymptotes).
  • 1 horizontal asymptote at \(y = 1\).

Conclusion

Therefore, the function \(f(x)\) has a total of

\[ \boxed{3} \]

asymptotes (2 vertical and 1 horizontal).