Sunny exponential sum

Today’s exponential sum is appropriate for a hot July day.

Each day the exponential sum page shows a different exponential sum with the month, day, and year in the denominators of an exponential sum. The graphs are formed by plotting the partial sums and connecting the dots. For example, today’s sum, is based on the partial sums

$S_n = \sum_{k=0}^n \exp\left(2\pi i \left(\frac{k}{7} + \frac{k^2}{1} + \frac{k^3}{18}\right ) \right )$

with 7, 1, and 18 in the denominators.

The reason I went with American style dates, with month-day-year, is that it produces more variety from day to day than using either day-month-year or year-month-day.