1. **State the problem:** We need to solve the inequality $$a (x^2 - x - a) \cdot (\sqrt{x^2 - 4x + 4} - a) > 0$$ for each value of the parameter $a$.
2. **Simplify the expression inside the square root:** Note that $$x^2 - 4x + 4 = (x-2)^2,$$ so $$\sqrt{x^2 - 4x + 4} = |x-2|.$$ Thus, the inequality becomes
$$a (x^2 - x - a) (|x-2| - a) > 0.$$
3. **Analyze the factors:** The inequality is a product of three factors: $a$, $(x^2 - x - a)$, and $(|x-2| - a)$. The product is positive if an even number of factors are negative or all are positive.
4. **Consider cases based on $a$:**
- **Case 1: $a = 0$**
The inequality becomes $0 > 0$, which is false. So no solution.
- **Case 2: $a > 0$**
Rewrite inequality as
$$a (x^2 - x - a) (|x-2| - a) > 0,$$
Since $a > 0$, divide both sides by $a$ (positive, so inequality direction unchanged):
$$ (x^2 - x - a) (|x-2| - a) > 0.$$
- **Case 3: $a < 0$**
Divide both sides by $a$ (negative, so inequality direction reverses):
$$ (x^2 - x - a) (|x-2| - a) < 0.$$
5. **Analyze the quadratic $x^2 - x - a$:**
The roots are given by
$$x = \frac{1 \pm \sqrt{1 + 4a}}{2}.$$
- For $a \geq -\frac{1}{4}$, roots are real.
- For $a < -\frac{1}{4}$, no real roots, so $x^2 - x - a$ always positive (since leading coefficient positive).
6. **Analyze $|x-2| - a$:**
- For $a > 0$, $|x-2| - a > 0$ means $|x-2| > a$, i.e., $x < 2 - a$ or $x > 2 + a$.
- For $a < 0$, $|x-2| - a > 0$ always true because $|x-2| \geq 0$ and $-a > 0$.
7. **Summarize solution for $a > 0$:**
Solve
$$(x^2 - x - a)(|x-2| - a) > 0.$$
This product is positive when both factors are positive or both negative.
- Find intervals where $x^2 - x - a > 0$ and $|x-2| - a > 0$.
- Find intervals where $x^2 - x - a < 0$ and $|x-2| - a < 0$.
8. **Summarize solution for $a < 0$:**
Solve
$$(x^2 - x - a)(|x-2| - a) < 0.$$
Since $a < 0$, $-a > 0$, so $|x-2| - a = |x-2| + |a| > 0$ always.
Thus, inequality reduces to
$$x^2 - x - a < 0.$$
- For $a < -\frac{1}{4}$, no real roots, so $x^2 - x - a > 0$ always, no solution.
- For $-\frac{1}{4} \leq a < 0$, solution is
$$\frac{1 - \sqrt{1 + 4a}}{2} < x < \frac{1 + \sqrt{1 + 4a}}{2}.$$
9. **Final answer:**
- For $a = 0$: no solution.
- For $a > 0$: solve
$$(x^2 - x - a)(|x-2| - a) > 0$$ using intervals defined by roots of $x^2 - x - a$ and points $2 \pm a$.
- For $a < 0$:
- If $a < -\frac{1}{4}$, no solution.
- If $-\frac{1}{4} \leq a < 0$, solution is
$$\frac{1 - \sqrt{1 + 4a}}{2} < x < \frac{1 + \sqrt{1 + 4a}}{2}.$$
Inequality Parameter E992B4
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.