(4n+2)π12(4 n+2) \frac{\pi}{12}(4n+2)12π
(4n+1)π12(4 n+1) \frac{\pi}{12}(4n+1)12π
(4n−1)π12(4 n-1) \frac{\pi}{12}(4n−1)12π
3π4\frac{3 \pi}{4}43π