Where does the seven come from?

1 · John Cook · June 10, 2020, 11:20 p.m.
Here’s a plot of exp(6it)/2 + exp(20it)/3: Notice that the plot has 7-fold symmetry. You might expect 6-fold symmetry from looking at the equation. Where did the 7 come from? I produced the plot using the code from this post, changing the line defining the function to plot to def f(t): return exp(6j*t)/2 + exp(20j*t)/3 […]...