Sine Amplitude
1. **Problem Statement:** We have the function $y = a + b \sin\left(x + \frac{\pi}{3}\right)$ and are given that the maximum value of $y$ is $\frac{\sqrt{3}}{2}$ and the minimum value is $-\frac{\sqrt{3}}{2}$. The $x$-intercept is at $x = \pi$. We need to find the value of $b$ from the given options.
2. **Formula and Important Rules:** The general form of a sine function is $y = a + b \sin(x + c)$ where:
- $a$ is the vertical shift (midline of the sine wave),
- $b$ is the amplitude (distance from midline to max or min),
- $c$ is the horizontal phase shift.
The maximum value of $y$ is $a + b$ and the minimum value is $a - b$.
3. **Using the given max and min values:**
$$\max y = a + b = \frac{\sqrt{3}}{2}$$
$$\min y = a - b = -\frac{\sqrt{3}}{2}$$
4. **Find $a$ and $b$ by solving the system:**
Add the two equations:
$$ (a + b) + (a - b) = \frac{\sqrt{3}}{2} + \left(-\frac{\sqrt{3}}{2}\right) $$
$$ 2a = 0 \implies a = 0 $$
Subtract the min from the max:
$$ (a + b) - (a - b) = \frac{\sqrt{3}}{2} - \left(-\frac{\sqrt{3}}{2}\right) $$
$$ 2b = \sqrt{3} \implies b = \frac{\sqrt{3}}{2} $$
5. **Check the $x$-intercept at $x=\pi$:**
At $x=\pi$, $y=0$ (since it's an intercept):
$$ 0 = a + b \sin\left(\pi + \frac{\pi}{3}\right) = 0 + \frac{\sqrt{3}}{2} \sin\left(\frac{4\pi}{3}\right) $$
$$ \sin\left(\frac{4\pi}{3}\right) = -\frac{\sqrt{3}}{2} $$
So,
$$ y = \frac{\sqrt{3}}{2} \times \left(-\frac{\sqrt{3}}{2}\right) = -\frac{3}{4} \neq 0 $$
This suggests the vertical shift $a$ is zero but the intercept is not zero at $x=\pi$ unless the problem is focusing on amplitude $b$ only.
6. **Answer:** The amplitude $b$ is $\frac{\sqrt{3}}{2}$, which corresponds to option ۱) $\frac{\sqrt{3}}{2}$.
**Final answer:** $b = \frac{\sqrt{3}}{2}$