Sinusoidal Graph 4C1229
1. **State the problem:**
We need to sketch a sinusoidal function with period 8, amplitude 5, axis at $y=-1$, and 2 full cycles.
2. **Formula and explanation:**
A sinusoidal function can be written as
$$y = A \sin\left(\frac{2\pi}{T}x\right) + D$$
where $A$ is amplitude, $T$ is period, and $D$ is the vertical shift (axis).
3. **Apply given values:**
Amplitude $A=5$, period $T=8$, axis $D=-1$.
4. **Write the function:**
$$y = 5 \sin\left(\frac{2\pi}{8}x\right) - 1 = 5 \sin\left(\frac{\pi}{4}x\right) - 1$$
5. **Calculate max and min values:**
Maximum: $D + A = -1 + 5 = 4$
Minimum: $D - A = -1 - 5 = -6$
6. **Number of cycles:**
Two full cycles means the function completes 2 periods over the x-range. Since one period is 8, two periods span $2 \times 8 = 16$ units.
7. **Graph description:**
- The sinusoidal wave oscillates between 4 and -6.
- The midline is at $y=-1$.
- The wave completes 2 cycles over the x-axis.
- The x-axis is labeled "Time" with increments every 2 units.
- The y-axis is labeled "height" with values from -6 to 5.
This matches the problem's description and confirms the function and graph characteristics.
**Final answer:**
$$y = 5 \sin\left(\frac{\pi}{4}x\right) - 1$$