1. Sketching Graphs
Maths Methods Unit 1

2. When we talk about sketching a graph, we mean drawing a diagram showing the main features — not a true scale graph showing every point plotted accurately using a computer package or other means.
To sketch a quadratic graph, the following features should generally be apparent or labelled:
The y-intercept
Any x-intercepts if they exist
The turning point coordinates

3. Turning Point Form

4. Example 1 - the turning point form

5. Example 1

6. Example 1

7. Example 2 – the turning point form

8. Example 2 – the turning point form

9. Polynomial Form y = ax2 + bx + c
Intercept Method

10. Polynomial Form y = ax2 + bx + c Intercept Method
The coordinates of the turning point are

11. Polynomial Form y = ax2 + bx + c Intercept Method
The y-coordinate of the turning point may be found by substituting the x-coordinate
into the original equation.

12. Example 3 – Intercept Method
Sketch the graph y = x2 + 10x + 25

13. Example 3

14. Example 4
Sketch the graph y = x2 − 16

15. Example 4

16. Example 5
Sketch the graph y = −2x2 + 11x − 15

17. Example 5
Sketch the graph y = −2x2 + 11x − 15