Edexcel IGCSE Maths

Revision Notes

3.5.1 Coordinates

What are coordinates?

  • When we want to plot a point on a graph we need to know where to put it
  • If the horizontal axis is labelled x and the vertical axis is labelled y, then the x and y coordinates are how far we go along the x and y axes to plot the point

What can we do with coordinates?

  • If we have two points with coordinates (x1, y1) and (x2, y2) then we should be able to find
    • the gradient of the line through them
    • the midpoint of the two points
    • the distance between the two points
  • Don’t get fazed by the horrid notation (x1, y1) – this is just “point 1” and the other is “point 2” so we put the little numbers (subscripts) in so that we know which coordinate we are referring to. In questions there’ll be lots of nice numbers
    Here’s how we do each of those:

Coordinates RN, downloadable IGCSE & GCSE Maths revision notes

  • You should also know that three points A, B and C lie on the same STRAIGHT LINE if AB and AC (or BC) have the same gradient

Exam Tip

If in doubt, SKETCH IT!
A quick, reasonably accurate sketch can make things a lot clearer.

Worked Example

Coordinates Worked Example 1, downloadable IGCSE & GCSE Maths revision notes

Inequalities on a graph - Interpreting Example 2, IGCSE & GCSE Maths revision notes

Coordinates Worked Example 2, downloadable IGCSE & GCSE Maths revision notes


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