Revise how to plot a linear equation graph. Learn how to read x and y coordinates from a graph in this BBC Bitesize maths KS3 guide.

Image via Wikipedia This is the second post (here’s the first one) about an approach to introducing the derivative to calculus students that is counter to what I’ve seen in textbooks and other ...

They slope in opposite directions, one has a positive gradient and the other has a negative gradient. The product of their gradients is -1, which means their gradients multiply to -1.