Quadratic graphs · Year 10
In Year 10 you learn: plotting quadratic graphs.
The graph of a quadratic y = ax² + bx + c is a smooth curve called a parabola: ∪-shaped when a is positive and ∩-shaped when a is negative. Its key features — roots, y-intercept and turning point — can all be found from the equation.
Key facts
- y-intercept: put x = 0, so it is the point (0, c).
- a > 0 gives a ∪ shape with a minimum; a < 0 gives a ∩ shape with a maximum.
- The discriminant b² − 4ac tells you whether the graph meets the x-axis twice, once or not at all.