Welcome Welcome to the fifteenth Autograph Newsletter! Each jam-packed edition looks at a specific topic in mathematics and how Autograph can help engage students and enable them to understand the key concepts better.
 Introduction Quadratic graphs and Autograph go together like toast and butter. Indeed, even the most tech-reluctant of teachers may see the benefit of drawing quadratic curves on Autograph. But to leave it at that is a crime against mathematics, because the software can offer so much more. In this newsletter we will look at how to develop the students’ knowledge and understanding of quadratic graphs in a dynamic and interactive way, starting with plotting curves from tables of values and culminating with a beautiful quadratic relationship. I hope you find something useful amongst all of this!
 Diagnostic Question Diagnostic questions are ideal to use at the start of the lesson to enable you to get a quick and accurate picture of your students’ levels of understanding. They are designed in such a way that common misconceptions that your students may hold should steer them to one of the incorrect answers, thus allowing you to learn where the problems lie from their responses. Typically I give my class 30 seconds thinking time and then ask them to hold up their fingers: 1 for A, 2 for B, etc.
 Free Online Autograph Activity Find the Curve What have these invisible curves got to do with y = x²? These Autograph activities do not require the full version of Autograph to run them. You just need to install the free Autograph Player (you will be guided through how to do this), which means you can use these activities in the classroom or set them for your students to do at home.
Ideas for Development
The following ideas for developing the topic of quadratic graphs require the full version of Autograph.
This file can be used to encourage students to spot the key features of quadratic curves to enable them to make a good sketch.
Challenge: Sketch y = x² – 4
 • How do you know where it crosses the y-axis? • How do you know where it crosses the x-axis? • How can you work out its minimum point? • Can you figure out some other points? For example, when x = 1, y = ?
Any time a student finds a point, get them to come up and either use the  Scribble tool to mark it, or  drag one of the circled points into position
 • When your students are ready, test their predictions by turning on  Slow Plot mode and  enter in the relevant equation. • You can then use this same approach to analyse the key features of any quadratic graph
Activity 2 – Different Forms of Quadratic Graphs (factorised and completing the square)
This file can be used to investigate how the different forms of quadratic expressions are represented graphically.
 • The green curve is y = x² and is used for reference • The red curve is in factorised form, y = (x + a)(x + b) • The blue curve is in completing the square form, y = (x + c)² + d • Students can use the  constant controller to investigate what happens to the equation of the curves and their position when the values of constants a, b, c and d are altered • Can students summarise what effect each letter has on the equation and the position of the curve? • Can they explain why this is the case? • Can students change the value of c and d to make the blue curve sit on top of the red curve? • Can students change the value of a and b to make the red curve sit on top of the blue curve? Why not?
Activity 3 – The Discriminant