1. **State the problem:** Find the derivative of the function $$f(x) = \frac{x^2 - x - 2}{x^2 - 6x + 9}$$.
2. **Recall the formula:** For a function $$f(x) = \frac{u(x)}{v(x)}$$, the derivative is given by the quotient rule:
$$
f'(x) = \frac{u'(x)v(x) - u(x)v'(x)}{[v(x)]^2}
$$
where $$u(x) = x^2 - x - 2$$ and $$v(x) = x^2 - 6x + 9$$.
3. **Find the derivatives of numerator and denominator:**
$$
u'(x) = \frac{d}{dx}(x^2 - x - 2) = 2x - 1$$
$$v'(x) = \frac{d}{dx}(x^2 - 6x + 9) = 2x - 6$$
4. **Apply the quotient rule:**
$$
f'(x) = \frac{(2x - 1)(x^2 - 6x + 9) - (x^2 - x - 2)(2x - 6)}{(x^2 - 6x + 9)^2}
$$
5. **Expand the terms in the numerator:**
- First term:
$$
(2x - 1)(x^2 - 6x + 9) = 2x^3 - 12x^2 + 18x - x^2 + 6x - 9 = 2x^3 - 13x^2 + 24x - 9
$$
- Second term:
$$
(x^2 - x - 2)(2x - 6) = 2x^3 - 6x^2 - 2x^2 + 6x - 4x + 12 = 2x^3 - 8x^2 + 2x + 12
$$
6. **Subtract the second term from the first:**
$$
(2x^3 - 13x^2 + 24x - 9) - (2x^3 - 8x^2 + 2x + 12) = 2x^3 - 13x^2 + 24x - 9 - 2x^3 + 8x^2 - 2x - 12
$$
$$
= (2x^3 - 2x^3) + (-13x^2 + 8x^2) + (24x - 2x) + (-9 - 12) = -5x^2 + 22x - 21
$$
7. **Write the derivative:**
$$
f'(x) = \frac{-5x^2 + 22x - 21}{(x^2 - 6x + 9)^2}
$$
8. **Simplify denominator if possible:** Note that $$x^2 - 6x + 9 = (x - 3)^2$$, so denominator is $$((x - 3)^2)^2 = (x - 3)^4$$.
**Final answer:**
$$
f'(x) = \frac{-5x^2 + 22x - 21}{(x - 3)^4}
$$
Derivative Rational Dcf0B9
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