(4n+1)π/2(4 n+1) \pi / 2(4n+1)π/2
−(1−4n)π/2-(1-4 n) \pi / 2−(1−4n)π/2
2nπ2 \mathrm{n} \pi2nπ
−(4n−1)π/2-(4 n-1) \pi / 2−(4n−1)π/2