Edexcel IGCSE Maths

Revision Notes

2.17.1 Inequalities on Graphs - Drawing

How do we draw inequalities on a graph?

  • First, see Straight Line Graphs and Linear Inequalities

Once you do…

  1. DRAW the line (as if using “=”) for each inequality
    Use a solid line for ≤ or ≥ (to indicate the line is included)
    Use dotted line for < or > (to indicate the line is not included)
  2. DECIDE which side of line is wanted:
    Below line if ≤ or <
    Above line if ≥ or >
    (Use the point (0, 0) as a test if unsure)
  3. Shade UNWANTED side of each line (unless the question says otherwise)
    This is because it is easier, with pen/pencil/paper at least, to see which region has not been shaded at all than it is to look for a region that has been shaded 2-3 times or more
    (Graphing software often shades the area that is required but this is easily overcome by reversing the inequality sign)

Worked Example

Inequalities on a graph - Drawing Worked Example, downloadable IGCSE & GCSE Maths revision notes

Linear-Inequalities-on-a-Graph, downloadable IGCSE & GCSE Maths revision notes

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