1. **State the problem:** Fit a quadratic function in vertex form to the data points: $(-3,-5), (-2,-2), (0,1), (1,2), (2,1.5), (3,0), (3.5,-1), (4,-2)$, where the parabola opens downward and has a vertex near $(1,2)$.
2. **Recall the vertex form of a quadratic function:**
$$y = a(x - h)^2 + k$$
where $(h,k)$ is the vertex and $a$ determines the opening direction and width.
3. **Identify vertex:** Given vertex near $(1,2)$, so $h=1$, $k=2$.
4. **Use a data point to find $a$:** Choose point $(0,1)$.
Substitute into vertex form:
$$1 = a(0 - 1)^2 + 2$$
$$1 = a(1)^2 + 2$$
$$1 = a + 2$$
Subtract 2 from both sides:
$$1 - 2 = a$$
$$a = -1$$
5. **Write the quadratic function:**
$$y = -1(x - 1)^2 + 2$$
6. **Verify with another point:** Check $(2,1.5)$:
$$y = -1(2 - 1)^2 + 2 = -1(1)^2 + 2 = -1 + 2 = 1$$
The actual point is $(2,1.5)$, close but not exact, indicating a good fit.
**Final answer:**
$$\boxed{y = -(x - 1)^2 + 2}$$
Vertex Form Fit C61D94
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