The most famous cyclic functions are the trigonometric functions -- in particular, sine and cosine. Trigonometry is beyond the scope of this course, but we can still look at cycles as a kind of function, without worrying about closed or recursive formulas to describe them. The general method of finding formulas is to start with a sine curve and to find a way to make the curve fit the data. This is similar to finding a "line of best fit" by changing the slope and intercept on the linear equation y = x.
Materials Needed: graph paper
Groups: Discuss questions about the homework. In particular, talk about Problem H2 and share the methods for solving it. Note that there is an algebraic equivalent to "undoing an exponent": taking a logarithm. (Logarithms are beyond the scope of this course, but it's important to acknowledge that such an inverse operation exists.)
Groups: Review the list of functions from the previous session. At least two more kinds of functions will be added to that list during this session.