(1-1/3+1/5-1/7+1/9-1/11+1/13-1/15+1/17)×4
=[(1-1/3)+(1/5-1/7)+(1/9-1/11)+(1/13-1/15)+1/17]×4
=(2/3+2/35+2/99+2/195+1/17)×4
=3.25236593
呵呵!还是用计算器吧!
(1-1/3+1/5-1/7+1/9-1/11+1/13-1/15+1/17)*4 = 3.2523659347189
厉害
等于圆周率π的近似值 你可以查看这个网址 http://bbs2.iyaya.com/talk/t-1-284103-0.html