1. **Stating the problem:**
We need to complete the sign table for $N_1(x)$, $N_2(x)$, $D_1(x)$, and $D_2(x)$, then solve the inequality $$\frac{N_1(x) \cdot N_2(x)}{D_1(x) \cdot D_2(x)} \leq 0$$ and deduce the solutions for $$\frac{4 - x^2}{2x - 3x^2} \leq 0.$$
2. **Given sign information:**
- $D_1(x)$ is negative on $(-\infty,0)$, zero at $0$, positive on $(0,2)$, zero at $2$, negative on $(2,+\infty)$.
- $D_2(x)$ is positive on $(-\infty,2)$, zero at $2$, negative on $(2,+\infty)$.
- Their product $D_1(x) \cdot D_2(x)$ is negative on $(-\infty,0)$, positive on $(0,2)$, zero at $0$ and $2$, negative on $(2,+\infty)$.
3. **(i) Complete the sign table for $N_1(x)$ and $N_2(x)$:**
Since $N_1(x) \geq 0$ is given, and the problem states $N_1(x) \geq 0$ on $[-2,0]$ (from the graph description), we can infer:
- $N_1(x) \geq 0$ on $[-2,0]$ and negative elsewhere.
For $N_2(x)$, no explicit sign info is given, so we assume it is positive on the domain where the product is considered.
4. **(ii) Solve the inequality $$\frac{N_1(x) \cdot N_2(x)}{D_1(x) \cdot D_2(x)} \leq 0.$$**
- The fraction is less than or equal to zero when the numerator and denominator have opposite signs or numerator is zero.
- Since $N_1(x) \geq 0$ on $[-2,0]$ and $N_2(x)$ is positive, numerator $\geq 0$ on $[-2,0]$.
- Denominator $D_1(x) \cdot D_2(x)$ is negative on $(-\infty,0)$, positive on $(0,2)$, zero at $0$ and $2$, negative on $(2,+\infty)$.
Check intervals:
- For $x \in (-\infty,-2)$: numerator negative, denominator negative $\Rightarrow$ fraction positive $>0$ (not solution).
- For $x \in [-2,0)$: numerator $\geq 0$, denominator negative $\Rightarrow$ fraction $\leq 0$ (solution).
- At $x=0$: denominator zero, fraction undefined.
- For $x \in (0,2)$: numerator positive, denominator positive $\Rightarrow$ fraction positive $>0$ (not solution).
- At $x=2$: denominator zero, fraction undefined.
- For $x > 2$: numerator positive, denominator negative $\Rightarrow$ fraction negative $<0$ (solution).
So solution set is $$[-2,0) \cup (2,+\infty).$$
5. **(iii) Solve $$\frac{4 - x^2}{2x - 3x^2} \leq 0.$$**
Rewrite numerator and denominator:
- Numerator: $4 - x^2 = (2 - x)(2 + x)$
- Denominator: $2x - 3x^2 = x(2 - 3x)$
Sign analysis:
- Numerator zero at $x = \pm 2$.
- Denominator zero at $x=0$ and $x=\frac{2}{3}$.
Intervals to test: $(-\infty, -2)$, $(-2,0)$, $(0, \frac{2}{3})$, $(\frac{2}{3}, 2)$, $(2, +\infty)$.
Check signs:
- $x < -2$: numerator positive (since $4 - x^2 > 0$ is false, actually negative), denominator negative (since $x$ negative, $2-3x$ positive), so numerator negative, denominator negative, fraction positive $>0$ (not solution).
- $-2 < x < 0$: numerator positive, denominator negative, fraction negative $<0$ (solution).
- $0 < x < \frac{2}{3}$: numerator positive, denominator positive, fraction positive $>0$ (not solution).
- $\frac{2}{3} < x < 2$: numerator positive, denominator negative, fraction negative $<0$ (solution).
- $x > 2$: numerator negative, denominator negative, fraction positive $>0$ (not solution).
Include points where fraction equals zero:
- Numerator zero at $x=\pm 2$, fraction zero.
- Denominator zero at $x=0, \frac{2}{3}$, fraction undefined.
Final solution:
$$[-2,0) \cup \left(\frac{2}{3}, 2\right].$$
Inequality Solution 00A483
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.