Quadratic Functions and Equations in One Variable
Parabola
The U-shaped curve of a quadratic function; it opens upward if a is positive and downward if a is negative.
| English | Parabola |
|---|---|
| Bahasa Melayu | Parabola |
| 中文 | 抛物线 |
How it is used
The graph of y = x² − 4x + 3 is a parabola opening upward (a = 1 > 0); it cuts the x-axis at x = 1 and x = 3 and has its lowest point at (2, −1).
Where it shows up in SPM
The shape of every quadratic graph (Form 4). Paper 2 asks you to sketch or interpret parabolas, marking the x-intercepts (roots), the y-intercept, and the turning point, and to state where the curve is above or below the x-axis.
Don't confuse it with
Open the chapter: Quadratic Functions and Equations in One Variable →
Frequently asked questions
How do I know if a parabola opens up or down?
Look at the coefficient a. If a is positive the parabola opens upward and has a minimum turning point; if a is negative it opens downward and has a maximum turning point.
For y = −2x² + x + 3, a = −2, so it opens downward.
What key points should I mark when sketching a parabola?
Mark the roots where it crosses the x-axis, the y-intercept (the value of c), and the turning point. Also show whether it opens up or down.
These few points let you draw an accurate sketch and earn the method marks in Paper 2.