Question: 2 Use the quadratic rule $y = x^2 - 1$ to complete these tasks.
a Complete the table of values.
$x$ -2 -1 0 1 2
$y$
b Draw a set of axes using a scale that suits the numbers in your table. Then plot the points to form a parabola.
c State these features.
i Type of turning point ii Axis of symmetry
iii Coordinates of the turning point iv The coordinates of the y-intercept
v The coordinates of the x-intercepts
Graph shape: a parabola opening upwards, centered on the y-axis, with turning point at (0, -1); it passes through points (-2, 3), (-1, 0), (0, -1), (1, 0), and (2, 3). position_hint: center
1. **State the problem:** We are given the quadratic function $$y = x^2 - 1$$ and need to complete a table of values, plot the points, and identify key features of the parabola.
2. **Complete the table of values:**
Use the formula $$y = x^2 - 1$$ to find $y$ for each $x$.
- For $x = -2$: $$y = (-2)^2 - 1 = 4 - 1 = 3$$
- For $x = -1$: $$y = (-1)^2 - 1 = 1 - 1 = 0$$
- For $x = 0$: $$y = 0^2 - 1 = 0 - 1 = -1$$
- For $x = 1$: $$y = 1^2 - 1 = 1 - 1 = 0$$
- For $x = 2$: $$y = 2^2 - 1 = 4 - 1 = 3$$
Completed table:
| $x$ | -2 | -1 | 0 | 1 | 2 |
|-----|----|----|---|---|---|
| $y$ | 3 | 0 | -1| 0 | 3 |
3. **Plot the points:**
Plot the points $(-2,3)$, $(-1,0)$, $(0,-1)$, $(1,0)$, and $(2,3)$ on a coordinate plane.
4. **State the features:**
i. **Type of turning point:** Since the coefficient of $x^2$ is positive, the parabola opens upwards, so the turning point is a minimum.
ii. **Axis of symmetry:** The parabola is symmetric about the vertical line through the vertex, which is $x=0$.
iii. **Coordinates of the turning point:** The vertex is at $(0, -1)$.
iv. **Coordinates of the y-intercept:** When $x=0$, $y=-1$, so the y-intercept is $(0, -1)$.
v. **Coordinates of the x-intercepts:** Solve $x^2 - 1 = 0$:
$$x^2 = 1$$
$$x = \pm 1$$
So the x-intercepts are $(-1, 0)$ and $(1, 0)$.
**Final answers:**
- Table: $y$ values are 3, 0, -1, 0, 3 for $x = -2, -1, 0, 1, 2$ respectively.
- Turning point: minimum at $(0, -1)$.
- Axis of symmetry: $x=0$.
- y-intercept: $(0, -1)$.
- x-intercepts: $(-1, 0)$ and $(1, 0)$.
This completes the tasks.