π2\frac{\pi}{2}2π
(4n+1)π2(4 n+1) \frac{\pi}{2}(4n+1)2π
(2n+1)n2(2 n+1) \frac{n}{2}(2n+1)2n
(2n+1)π3(2 n+1) \frac{\pi}{3}(2n+1)3π