1. **Problem 1: Solve for $b$ given the integral equation**
Given:
$$\frac{1}{b-a} \int_a^b f(x) \, dx = 2$$
with $a=0$ and $f(x) = 2 + 7x - x^3$, and the equation:
$$(2 + 7b - b^3) = 16$$
2. **Step 1: Write the integral and evaluate it**
$$\int_0^b (2 + 7x - x^3) \, dx = \left[2x + \frac{7x^2}{2} - \frac{x^4}{4}\right]_0^b = 2b + \frac{7b^2}{2} - \frac{b^4}{4}$$
3. **Step 2: Use the average value formula**
$$\frac{1}{b-0} \int_0^b f(x) \, dx = 2 \implies \frac{1}{b} \left(2b + \frac{7b^2}{2} - \frac{b^4}{4}\right) = 2$$
4. **Step 3: Simplify the equation**
$$2 + \frac{7b}{2} - \frac{b^3}{4} = 2$$
5. **Step 4: Subtract 2 from both sides**
$$\frac{7b}{2} - \frac{b^3}{4} = 0$$
6. **Step 5: Multiply both sides by 4 to clear denominators**
$$4 \times \left(\frac{7b}{2} - \frac{b^3}{4}\right) = 4 \times 0$$
$$2 \times 7b - b^3 = 0$$
$$14b - b^3 = 0$$
7. **Step 6: Factor out $b$**
$$b(14 - b^2) = 0$$
8. **Step 7: Solve for $b$**
Either $b=0$ (not valid since denominator would be zero) or
$$14 - b^2 = 0 \implies b^2 = 14 \implies b = \sqrt{14} \approx 3.74$$
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**Final answer for problem 1:**
$$b = \sqrt{14} \approx 3.74$$
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1. **Problem 2: Find the position of the particle at $t = \frac{3\pi}{2}$ given velocity and initial position**
Given velocity:
$$v(t) = 1 - \sin t$$
Initial position:
$$x(\pi) = \pi$$
2. **Step 1: Write the position function as an integral of velocity**
$$x(t) = x(\pi) + \int_{\pi}^t v(s) \, ds = \pi + \int_{\pi}^t (1 - \sin s) \, ds$$
3. **Step 2: Compute the integral**
$$\int_{\pi}^t (1 - \sin s) \, ds = \int_{\pi}^t 1 \, ds - \int_{\pi}^t \sin s \, ds = (t - \pi) + (\cos t - \cos \pi)$$
4. **Step 3: Substitute $t = \frac{3\pi}{2}$**
$$x\left(\frac{3\pi}{2}\right) = \pi + \left(\frac{3\pi}{2} - \pi\right) + \left(\cos \frac{3\pi}{2} - \cos \pi\right)$$
5. **Step 4: Evaluate cosines**
$$\cos \frac{3\pi}{2} = 0, \quad \cos \pi = -1$$
6. **Step 5: Simplify**
$$x\left(\frac{3\pi}{2}\right) = \pi + \frac{\pi}{2} + (0 - (-1)) = \pi + \frac{\pi}{2} + 1 = \frac{3\pi}{2} + 1$$
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**Final answer for problem 2:**
$$x\left(\frac{3\pi}{2}\right) = \frac{3\pi}{2} + 1$$
Integral Position 4F7291
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