Set Identity And Functions
1. Problem ক: Given $g(t) = \frac{t^4 + t^2 + 1}{t^2}$, find $g(-3^{-1})$.
2. To solve, note that $-3^{-1} = -\frac{1}{3}$.
3. Substitute $t = -\frac{1}{3}$:
$$g\left(-\frac{1}{3}\right) = \frac{\left(-\frac{1}{3}\right)^4 + \left(-\frac{1}{3}\right)^2 + 1}{\left(-\frac{1}{3}\right)^2}.$$
4. Calculate each term:
$$\left(-\frac{1}{3}\right)^4 = \frac{1}{81}, \quad \left(-\frac{1}{3}\right)^2 = \frac{1}{9}.$$
5. So numerator:
$$\frac{1}{81} + \frac{1}{9} + 1 = \frac{1}{81} + \frac{9}{81} + \frac{81}{81} = \frac{91}{81}.$$
6. Denominator:
$$\frac{1}{9}.$$
7. Thus:
$$g\left(-\frac{1}{3}\right) = \frac{\frac{91}{81}}{\frac{1}{9}} = \frac{91}{81} \times 9 = \frac{91}{9}.$$
8. Problem খ: Show that $A \cup B = (A - B) \cup (B - A) \cup (A \cap B)$.
9. By definition,
- $A \cup B$ contains all elements in $A$ or $B$.
- $A - B$ elements in $A$ not in $B$.
- $B - A$ elements in $B$ not in $A$.
- $A \cap B$ elements in both.
10. Since union of these disjoint subsets covers all elements of $A$ and $B$, the equality holds.
11. Problem গ: Given $f(x) = \frac{4x+1}{4x-1}$ and equation $\frac{f(x+2)-1}{f(x-2)-1}+1 = 0$, find $x$.
12. Compute $f(x+2) - 1$:
$$f(x+2) - 1 = \frac{4(x+2)+1}{4(x+2)-1} - 1 = \frac{4x + 8 + 1}{4x + 8 - 1} - 1 = \frac{4x + 9}{4x + 7} - 1 = \frac{4x + 9 - (4x + 7)}{4x + 7} = \frac{2}{4x + 7}.$$
13. Compute $f(x-2) - 1$:
$$f(x-2) - 1 = \frac{4(x-2)+1}{4(x-2)-1} - 1 = \frac{4x -8 +1}{4x -8 -1} - 1 = \frac{4x - 7}{4x - 9} - 1 = \frac{4x -7 - (4x -9)}{4x -9} = \frac{2}{4x -9}.$$
14. Substitute into given equation:
$$\frac{\frac{2}{4x + 7}}{\frac{2}{4x - 9}} + 1 = 0 \implies \frac{2}{4x + 7} \times \frac{4x - 9}{2} + 1 = 0.$$
15. Simplify:
$$\frac{4x - 9}{4x + 7} + 1 = 0 \implies \frac{4x - 9 + 4x + 7}{4x + 7} = 0 \implies \frac{8x - 2}{4x + 7} = 0.$$
16. For fraction to be zero, numerator must be zero:
$$8x - 2 = 0 \implies x = \frac{1}{4}.$$
Final answers:
গ: $\boxed{\frac{1}{4}}$
ক: $\boxed{\frac{91}{9}}$
Slug: "set identity and functions"
Subject: "set theory and algebra"
Desmos: {"latex":"y=(4x+1)/(4x-1)","features":{"intercepts":true,"extrema":true}}
q_count: 3