Why do we want to know about straight lines and their equations?
- Straight Line Graphs (Linear Graphs) have lots of uses in mathematics – one use is in navigation
- We may want to know the equation of a straight line so we can program it into a computer that will plot the line on a screen, along with several others, to make shapes and graphics
How do we find the equation of a straight line?
- The general EQUATION of a straight line is y = mx + c
- where m is the gradient
- c is the y-axis intercept
- To find the EQUATION of a straight line you need TWO things:
- the gradient, m
- any point on the line
- You might find these things from a graph, another equation or two points
- You may be asked to give the equation in the form ax + by + c = 0
(especially if m is a fraction)
If in doubt, SKETCH IT!