1. The problem involves analyzing three quadratic functions:
$$f(x) = -3x^{2} + 4x + 1$$
$$f(x) = 4x^{2} + 4x + 5$$
$$f(x) = x^{2} + 2x + 1$$
We want to understand their graphs, especially the vertex of each parabola.
2. The vertex of a parabola given by $$f(x) = ax^{2} + bx + c$$ is found using the formula for the x-coordinate:
$$x = -\frac{b}{2a}$$
The y-coordinate is then:
$$y = f\left(-\frac{b}{2a}\right)$$
3. For the first function $$f(x) = -3x^{2} + 4x + 1$$:
- Here, $$a = -3$$, $$b = 4$$, $$c = 1$$.
- Calculate $$x$$ of vertex:
$$x = -\frac{4}{2 \times -3} = -\frac{4}{-6} = \frac{2}{3}$$
- Calculate $$y$$ of vertex:
$$y = -3\left(\frac{2}{3}\right)^{2} + 4\left(\frac{2}{3}\right) + 1 = -3\left(\frac{4}{9}\right) + \frac{8}{3} + 1 = -\frac{12}{9} + \frac{8}{3} + 1 = -\frac{4}{3} + \frac{8}{3} + 1 = \frac{4}{3} + 1 = \frac{7}{3}$$
So the vertex is at $$\left(\frac{2}{3}, \frac{7}{3}\right)$$.
4. For the second function $$f(x) = 4x^{2} + 4x + 5$$:
- Here, $$a = 4$$, $$b = 4$$, $$c = 5$$.
- Calculate $$x$$ of vertex:
$$x = -\frac{4}{2 \times 4} = -\frac{4}{8} = -\frac{1}{2}$$
- Calculate $$y$$ of vertex:
$$y = 4\left(-\frac{1}{2}\right)^{2} + 4\left(-\frac{1}{2}\right) + 5 = 4\left(\frac{1}{4}\right) - 2 + 5 = 1 - 2 + 5 = 4$$
So the vertex is at $$\left(-\frac{1}{2}, 4\right)$$.
5. For the third function $$f(x) = x^{2} + 2x + 1$$:
- Here, $$a = 1$$, $$b = 2$$, $$c = 1$$.
- Calculate $$x$$ of vertex:
$$x = -\frac{2}{2 \times 1} = -\frac{2}{2} = -1$$
- Calculate $$y$$ of vertex:
$$y = (-1)^{2} + 2(-1) + 1 = 1 - 2 + 1 = 0$$
So the vertex is at $$(-1, 0)$$.
6. Summary:
- The vertex of $$f(x) = -3x^{2} + 4x + 1$$ is at $$\left(\frac{2}{3}, \frac{7}{3}\right)$$.
- The vertex of $$f(x) = 4x^{2} + 4x + 5$$ is at $$\left(-\frac{1}{2}, 4\right)$$.
- The vertex of $$f(x) = x^{2} + 2x + 1$$ is at $$(-1, 0)$$.
These vertices represent the highest or lowest points on their respective parabolas depending on the sign of $$a$$ (negative $$a$$ means maximum, positive $$a$$ means minimum).
Parabola Vertices 618E83
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