About the lecture

In this mini-lecture, we introduce Topic A14 by exploring straight-line graphs in real contexts. In particular, we consider: (i) a graph depicting the cost of buying different amounts of petrol, from which we think about why the graph is a straight line and learn that the slope gives the cost per litre; (ii) the general principle that the slope of a graph is the rate at which the y variable changes with respect to the x variable; and (iii) a graph depicting the cost of a plumber with a call out charge, from which we see that this straight-line graph does not pass through the origin and that the y-intercept is the call out charge while the slope is the hourly rate.

About the lecturer

Keith Ball is a Professor of Mathematics and the University of Warwick. His research interests are in functional analysis, high-dimensional and discrete geometry, and information theory. From 2010-14, Professor Ball served as the scientific director of the International Centre for Mathematical Sciences (ICMS) based in Edinburgh. He was elected as a Fellow of the Royal Society in 2013 and awarded the Whitehead Prize by the London Mathematical Society in 1992. Professor Ball is the author of Strange Curves, Counting Rabbits, and other Mathematical Explorations (2006), a recreational maths book aimed at those familiar with basic calculus.