Education Technology


Activity Overview

Students use trigonometric functions to model biorhythmic activity. Whilst the psuedo science of biorhythms equates approximately to astrology, the activity content is applicable to graphing simple trigonometric functions involving only transformations. The alignment of days helps students understand the period of the function.


Recognise the graph of y = sin(x) and examine phase and period changes pertaining to the context of biorhythms.


  • Period
  • dilation
  • Transformation

About the Lesson

Students use their own birthday and the current date to determine the equation for their physical, emotional and intellectual cycles according to the study of biorhythms. Whilst the study of biorhythms is generally completed with Astrology – “a self-fulfilling prophetic vagueness” and “Where to find the Pixies, Gnomes and Fairies in your Garden”, the mathematics is applicable and the subject matter provides a level of tongue in cheek engagement and entertainment. Students use some of the less frequently used commands on the calculator such as DBD (days between dates) and MOD (modular arithmetic).