1. **Problem statement:** Given the function $f(x) = \frac{x^3 - 4x^2 + 1}{x - 2}$, find its domain, simplify the expression if possible, determine the nature of the discontinuity at $x=2$, and compute $\lim_{x \to 2} f(x)$.
2. **Domain:** The function is a rational function and is undefined where the denominator is zero. So, set denominator equal to zero:
$$x - 2 = 0 \implies x = 2$$
Thus, the domain is all real numbers except $x=2$.
3. **Simplify the expression:** Try to factor the numerator to see if $(x-2)$ is a factor:
Use polynomial division or factor by synthetic division:
Divide $x^3 - 4x^2 + 1$ by $x - 2$.
Perform polynomial division:
$$\frac{x^3 - 4x^2 + 1}{x - 2} = x^2 - 2x - 4 + \frac{\cancel{9}}{x - 2}$$
Since the remainder is 9, $(x-2)$ is not a factor, so no simplification by cancellation.
4. **Determine the discontinuity at $x=2$:** Since the denominator is zero at $x=2$ and the numerator is not zero at $x=2$ (evaluate numerator at 2: $2^3 - 4(2)^2 + 1 = 8 - 16 + 1 = -7 \neq 0$), the function has a vertical asymptote at $x=2$.
5. **Compute the limit as $x$ approaches 2:**
Calculate:
$$\lim_{x \to 2} \frac{x^3 - 4x^2 + 1}{x - 2}$$
Since direct substitution gives division by zero, analyze the limit from left and right:
- Numerator at $x=2$ is $-7$ (negative).
- Denominator approaches 0 from positive side when $x \to 2^+$ and from negative side when $x \to 2^-$.
Therefore:
$$\lim_{x \to 2^-} f(x) = \frac{-7}{0^-} = +\infty$$
$$\lim_{x \to 2^+} f(x) = \frac{-7}{0^+} = -\infty$$
The limit does not exist because the left and right limits are not equal.
**Final answers:**
- Domain: $\{x \in \mathbb{R} : x \neq 2\}$
- Simplified form: No simplification possible
- Discontinuity at $x=2$: Vertical asymptote
- Limit as $x \to 2$: Does not exist (left limit $+\infty$, right limit $-\infty$)
Rational Function Analysis 51Aede
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