Fermin is an athlete who trains daily following a routine of progressive training. Three days a week he approaches the track, which is 400 meters long in the lane 1. His training methodology is below described. During the initial laps he walks, beginning at 5 Km/H although continuously increasing his speed by 0.5 Km/H each lap. Fermin runs the last lap at 18 Km/H. When finishing the training Fermin has run 27 laps. This little story is presented as an example of linear growth, the increase in speed is 0.5 per lap; so if the increase is constant. If speed is plotted against laps, a straight line is shown.

VvsVuelta eng

Another analysis is possible to this case. If the variable plotted against time is the number of laps instead of speed, it is possible to identify that each lap is shorter than before, as a consequence of the faster movements of Fermin. Under this scope this story is a case of exponential growth.

V vs tiempo eng

In exponential growth the variable is not the only thingĀ increasedĀ with time, the growth rate also does it.

Lineal growth 1, 2, 3, 4, 5, 6, 7, 8…

Exponential growth 2, 4, 8, 16, 32, 64…