Edexcel IGCSE Maths 复习笔记 2.17.1 Inequalities on Graphs - Drawing

Edexcel IGCSE Maths 复习笔记 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 inequalityUse 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

Worked Example

转载自savemyexam

 

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