Quadratic Function A32Ade
1. The problem is to analyze the quadratic function given by the equation $y = kx^2 + 2x + 3$.
2. This is a quadratic function of the form $y = ax^2 + bx + c$, where $a = k$, $b = 2$, and $c = 3$.
3. Important rules for quadratic functions:
- The graph is a parabola.
- If $a > 0$, the parabola opens upwards; if $a < 0$, it opens downwards.
- The vertex of the parabola is at $x = -\frac{b}{2a}$.
- The y-intercept is at $y = c$.
4. To find the vertex:
$$x = -\frac{2}{2k} = -\frac{1}{k}$$
5. Substitute $x = -\frac{1}{k}$ back into the function to find the y-coordinate of the vertex:
$$y = k\left(-\frac{1}{k}\right)^2 + 2\left(-\frac{1}{k}\right) + 3 = k\frac{1}{k^2} - \frac{2}{k} + 3 = \frac{1}{k} - \frac{2}{k} + 3 = -\frac{1}{k} + 3$$
6. The vertex is at $$\left(-\frac{1}{k}, -\frac{1}{k} + 3\right)$$.
7. The y-intercept is when $x=0$:
$$y = k(0)^2 + 2(0) + 3 = 3$$
8. The x-intercepts (roots) can be found by solving:
$$kx^2 + 2x + 3 = 0$$
Using the quadratic formula:
$$x = \frac{-2 \pm \sqrt{4 - 12k}}{2k}$$
9. The discriminant is $\Delta = 4 - 12k$.
- If $\Delta > 0$, two real roots.
- If $\Delta = 0$, one real root.
- If $\Delta < 0$, no real roots.
Summary:
- Vertex: $$\left(-\frac{1}{k}, -\frac{1}{k} + 3\right)$$
- Y-intercept: 3
- X-intercepts depend on $k$ and are given by $$x = \frac{-2 \pm \sqrt{4 - 12k}}{2k}$$