1. **Stating the problem:**
We are given the system:
$$a + b = \sqrt{3}, \quad a - b = \sqrt{2}$$
and the equations:
$$8(a^2 + b^2)(a^3 - b^3) = 55\sqrt{2}$$
$$16a^2b^2(a^4 + b^4) = 49$$
We want to understand how to work with these expressions and possibly find values or simplify.
2. **Step 1: Find $a$ and $b$ from the system**
Add the two equations:
$$a + b = \sqrt{3}$$
$$a - b = \sqrt{2}$$
Adding gives:
$$2a = \sqrt{3} + \sqrt{2} \implies a = \frac{\sqrt{3} + \sqrt{2}}{2}$$
Subtracting gives:
$$2b = \sqrt{3} - \sqrt{2} \implies b = \frac{\sqrt{3} - \sqrt{2}}{2}$$
3. **Step 2: Calculate $a^2$ and $b^2$**
$$a^2 = \left(\frac{\sqrt{3} + \sqrt{2}}{2}\right)^2 = \frac{(\sqrt{3} + \sqrt{2})^2}{4} = \frac{3 + 2\sqrt{6} + 2}{4} = \frac{5 + 2\sqrt{6}}{4}$$
$$b^2 = \left(\frac{\sqrt{3} - \sqrt{2}}{2}\right)^2 = \frac{(\sqrt{3} - \sqrt{2})^2}{4} = \frac{3 - 2\sqrt{6} + 2}{4} = \frac{5 - 2\sqrt{6}}{4}$$
4. **Step 3: Calculate $a^2 + b^2$**
$$a^2 + b^2 = \frac{5 + 2\sqrt{6}}{4} + \frac{5 - 2\sqrt{6}}{4} = \frac{5 + 5}{4} = \frac{10}{4} = \frac{5}{2}$$
5. **Step 4: Calculate $a^3 - b^3$**
Use the identity:
$$a^3 - b^3 = (a - b)(a^2 + ab + b^2)$$
We know $a - b = \sqrt{2}$.
Calculate $ab$:
$$ab = \left(\frac{\sqrt{3} + \sqrt{2}}{2}\right)\left(\frac{\sqrt{3} - \sqrt{2}}{2}\right) = \frac{(\sqrt{3})^2 - (\sqrt{2})^2}{4} = \frac{3 - 2}{4} = \frac{1}{4}$$
Calculate $a^2 + ab + b^2$:
$$a^2 + ab + b^2 = \frac{5}{2} + \frac{1}{4} = \frac{10}{4} + \frac{1}{4} = \frac{11}{4}$$
Therefore:
$$a^3 - b^3 = \sqrt{2} \times \frac{11}{4} = \frac{11\sqrt{2}}{4}$$
6. **Step 5: Verify the first big equation**
$$8(a^2 + b^2)(a^3 - b^3) = 8 \times \frac{5}{2} \times \frac{11\sqrt{2}}{4} = 8 \times \frac{55\sqrt{2}}{8} = 55\sqrt{2}$$
This matches the given equation.
7. **Step 6: Calculate $a^4 + b^4$**
Use the identity:
$$a^4 + b^4 = (a^2 + b^2)^2 - 2a^2b^2$$
Calculate $a^2b^2 = (ab)^2 = \left(\frac{1}{4}\right)^2 = \frac{1}{16}$
Calculate:
$$a^4 + b^4 = \left(\frac{5}{2}\right)^2 - 2 \times \frac{1}{16} = \frac{25}{4} - \frac{2}{16} = \frac{25}{4} - \frac{1}{8} = \frac{50}{8} - \frac{1}{8} = \frac{49}{8}$$
8. **Step 7: Verify the second big equation**
$$16a^2b^2(a^4 + b^4) = 16 \times \frac{1}{16} \times \frac{49}{8} = 1 \times \frac{49}{8} = \frac{49}{8}$$
The given equation states it equals 49, but the calculation yields $\frac{49}{8}$. This suggests a possible typo or misinterpretation in the problem statement.
**Summary:**
- We solved for $a$ and $b$.
- Verified the first equation exactly.
- Calculated $a^4 + b^4$ and found a discrepancy in the second equation.
This is how you approach such problems: solve the system, use algebraic identities, substitute, and verify step-by-step.
Solve System 1B6840
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