1-(1/(n+1))*(1/(n+1))=1-(1/((n+1)*(n+1)))=((n+1)*(n+1)-1)/(n+1)(n+1)=n/(n+1)*(n+2)/(n+1)
(1-1/2的平方)(1-1/3的平方)...(1-1/2001的平方)(1-1/2002的平方)=1/2*3/2*2/3*4/3*3/4*5/4=1/2*(2002+2)/(2002+1)=1002/2003
1-(1/(n+1))*(1/(n+1))=1-(1/((n+1)*(n+1)))=((n+1)*(n+1)-1)/(n+1)(n+1)=n/(n+1)*(n+2)/(n+1)
(1-1/2的平方)(1-1/3的平方)...(1-1/2001的平方)(1-1/2002的平方)=1/2*3/2*2/3*4/3*3/4*5/4=1/2*(2002+2)/(2002+1)=1002/2003