We find the period of the function f(x), given the functional equation f(x) = sqrt{2 - sqrt{3}}(f(x + 1) + f(x - 1)) for all real x.
Solving as a recurrence relation:
https://en.wikipedia.org/wiki/Linear_recurrence_with_constant_coefficients#Order_2
00:00 Periodic functions
00:50 Substitution & elimination
04:30 f(x ± 2)
08:32 Finding the period
10:18 Smaller periods?
