Maths That Predicts Behaviour
Graphs & Gradients
12 min · 2 worked examplesStudent plan
A straight line on a graph is a physical law you can read off with a ruler. Gradient, intercept, and what the slope of a V-I graph actually tells you.
After this lesson you can
- Read a gradient off a graph by counting squares
- Say what the gradient means, including its units
- Read the intercept and explain what a non-zero one is telling you
Every straight line is y = mx + c
A straight line needs only two numbers to describe it completely.
m is the gradient, which is how steep it is. c is the intercept, which is where it crosses the vertical axis.
That is the whole of y = mx + c. Nothing else about a straight line is unknown once you have those two.
In the full lesson
- Every straight line is y = mx + c
- Reading a gradient off the graph
- The units are the point
- The V-I graph of a resistor
- When the intercept is not zero
This lesson comes with the Student plan. The first module of Maths for Engineers is free.