Inequality Simplification 402Fac
1. **State the problem:** Solve the inequality $$\frac{x - 1}{x} - x < 1 - \frac{x}{n + 1}$$ for $x$.
2. **Rewrite the inequality:**
$$\frac{x - 1}{x} - x < 1 - \frac{x}{n + 1}$$
3. **Find a common denominator and simplify terms:**
First, rewrite each term clearly:
- Left side: $$\frac{x - 1}{x} - x = \frac{x - 1}{x} - \frac{x^2}{x} = \frac{x - 1 - x^2}{x} = \frac{-x^2 + x - 1}{x}$$
- Right side: $$1 - \frac{x}{n + 1} = \frac{(n + 1)}{n + 1} - \frac{x}{n + 1} = \frac{n + 1 - x}{n + 1}$$
4. **Rewrite inequality with these expressions:**
$$\frac{-x^2 + x - 1}{x} < \frac{n + 1 - x}{n + 1}$$
5. **Cross-multiply carefully, considering domain restrictions:**
$$(-x^2 + x - 1)(n + 1) < x(n + 1 - x)$$
6. **Expand both sides:**
Left side:
$$(-x^2 + x - 1)(n + 1) = -x^2(n + 1) + x(n + 1) - (n + 1)$$
Right side:
$$x(n + 1 - x) = x(n + 1) - x^2$$
7. **Bring all terms to one side:**
$$-x^2(n + 1) + x(n + 1) - (n + 1) - x(n + 1) + x^2 < 0$$
Simplify terms:
$$-x^2(n + 1) + x^2 - (n + 1) < 0$$
8. **Factor the $x^2$ terms:**
$$x^2(- (n + 1) + 1) - (n + 1) < 0$$
Simplify inside parentheses:
$$x^2(-n - 1 + 1) - (n + 1) < 0$$
$$x^2(-n) - (n + 1) < 0$$
9. **Rewrite inequality:**
$$-n x^2 - (n + 1) < 0$$
Multiply both sides by $-1$ (reverse inequality):
$$n x^2 + (n + 1) > 0$$
10. **Analyze the inequality:**
Since $x^2 \geq 0$ for all real $x$, and $n x^2 \geq 0$ if $n \geq 0$, then:
- If $n \geq 0$, then $n x^2 + (n + 1) \geq n + 1 > 0$ (assuming $n + 1 > 0$), so inequality holds for all $x$.
- If $n < 0$, the expression may be negative for some $x$.
11. **Domain restrictions:**
- $x \neq 0$ (denominator in original inequality)
- $n + 1 \neq 0$ (denominator in original inequality)
12. **Final conclusion:**
The inequality simplifies to $$n x^2 + (n + 1) > 0$$ with domain restrictions $x \neq 0$ and $n \neq -1$.
The solution depends on the value of $n$:
- For $n \geq 0$, the inequality holds for all $x \neq 0$.
- For $n < 0$, solve $$n x^2 + (n + 1) > 0$$ accordingly.
**Answer:** The inequality reduces to $$n x^2 + (n + 1) > 0$$ with $x \neq 0$ and $n \neq -1$.