An explanation of a neat circle puzzle involving combinatorics, graphs, Euler's characteristic formula and pascal's triangle. Music: Wyoming 307 by Time for ...
========== In my last video, I posed the following
question: If you take n points on a circle, then
connect every pair of them with a line, how many sections to these lines cut
the circle into? What was strange is that when n is less than 6, and when n is 10 for some reason, the answer is always a power of 2, but for
all other values of n, the answer seems completely unrelated
powers of 2. What love about this problem is that it brings together many
disparate concept: counting functions, graphs, one of Euler's famous
equations, and Pascal's triangle. You might be wondering if changing the
placement of points change the number of sections It actually can! For instance, watch how
this small region in the middle disappears if we adjust things so that
three lines go through the same point. B...