1. **State the problem:** We need to find the function $f(x) = 2 \sin(kx) + d$ that matches the given sinusoidal wave with amplitude 2, passing through the point $(0,-1)$, and x-axis labeled in multiples of $\pi$. The wave starts at $y=-1$ when $x=0$, indicating a vertical shift.
2. **Identify amplitude and vertical shift:** The amplitude is the coefficient before sine, which is 2. The vertical shift $d$ is the value of the function at $x=0$ because $\sin(0) = 0$, so:
$$f(0) = 2 \sin(k \cdot 0) + d = d = -1$$
Thus, $d = -1$.
3. **Determine the period and frequency $k$:** The period $T$ of $\sin(kx)$ is given by:
$$T = \frac{2\pi}{k}$$
From the graph, the wave completes one full cycle between $-\pi/3$ and $\pi/3$, which is a length of:
$$\pi/3 - (-\pi/3) = \frac{2\pi}{3}$$
So the period $T = \frac{2\pi}{3}$.
4. **Calculate $k$ using the period:**
$$k = \frac{2\pi}{T} = \frac{2\pi}{\frac{2\pi}{3}} = 3$$
5. **Write the final function:**
$$f(x) = 2 \sin(3x) - 1$$
6. **Summary:** The function has amplitude 2, frequency multiplier $k=3$, and vertical shift $-1$.
**Final answer:**
$$f(x) = 2 \sin(3x) - 1$$
Sinusoidal Function 189780
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