Education Technology

String Graphs Part2

Activity Overview

This is part two of a four part series. In this activity students are given two points that lie on a straight line, they determine the equation for each line that eventually forms a curved envelope that forms a parabola. In the second half of this activity students learn to use a parameter so that the family of graphs can be generated using a single equation.


Students determine the equation to a straight line given two points. In this activity they use a less familiar approach but more efficient approach by using the translational form of a straight line. This form is very quick to use and makes the identification of the subsequent patterns significantly easier. The Computer Algebra System in the calculator automatically converts the format to the more familiar y = mx + c.


  • Gradient
  • y = m (x - h) + k
  • Translation
  • Expand
  • Parameter

About the Lesson

Watch Activity Tutorial

Part Two of a Four Part Series. In this activity students determine the equation to a family of straight lines given two points for each line. Students then generate the family of straight lines by developing a general formula and corresponding parameter. A full series of videos are available for students to watch to assist with completing the activity or activity series.