405° is 45° beyond 360° and tan(45°) = 1, so tan(405°) = 1.
13pi/3 is pi/3 beyond 4pi (or 2 complete rotations; i.e. 2 rotations of 360°). pi/3 is the same as 60° and cot(60°) = 1/√3, so cot(13pi/3) = 1/√3 (=√3/3).
405° is 45° beyond 360° and tan(45°) = 1, so tan(405°) = 1.
13pi/3 is pi/3 beyond 4pi (or 2 complete rotations; i.e. 2 rotations of 360°). pi/3 is the same as 60° and cot(60°) = 1/√3, so cot(13pi/3) = 1/√3 (=√3/3).
