Quadratic Parabola 98F87C
1. The problem is to analyze the function $f(x) = x^2 - 4$.
2. This is a quadratic function in the form $ax^2 + bx + c$ where $a=1$, $b=0$, and $c=-4$.
3. Important rules for quadratics:
- The graph is a parabola.
- The vertex form is $f(x) = a(x-h)^2 + k$ where $(h,k)$ is the vertex.
- The axis of symmetry is $x = -\frac{b}{2a}$.
- The roots (x-intercepts) are found by solving $x^2 - 4 = 0$.
4. Find the vertex:
- Since $b=0$, axis of symmetry is $x=0$.
- Evaluate $f(0) = 0^2 - 4 = -4$.
- Vertex is at $(0, -4)$.
5. Find the roots:
- Solve $x^2 - 4 = 0$.
- Add 4 to both sides: $x^2 = 4$.
- Take square root: $x = \pm 2$.
- Roots are $x=2$ and $x=-2$.
6. The y-intercept is found by evaluating $f(0) = -4$.
7. Summary:
- Vertex: $(0, -4)$
- Roots: $x = -2, 2$
- Axis of symmetry: $x=0$
- Opens upward since $a=1 > 0$.
Final answer: The parabola $y = x^2 - 4$ has vertex at $(0,-4)$, roots at $x=\pm 2$, and opens upward.