=(2001/2002)×(2002+1)=2001+2001/2002=2002-1/2002或者=(2002-1)×(2002+1)÷2002=2002-1/2002
(2001/2002)*2003=(2001/2002)*(2002+1)=2001+2001/2002
=(2002+1)*(2002-1)/2002=(2002^2-1)/2002=2002+1/2002
......2001.9995004995004995004995的循环节哦