中老年体育男冲锋衣:1 1/3 1/9 1/27 1/18 ( )

(1+1/2)X(1-1/2)X(1+1/3)X......X(1-1/9) 1 1/3 1/9 1/27 1/18 ( ) 计算:(1-1/2^)·(1-1/3^)·(1-1/4^)……(1-1/9^)·(1-1/10^) 1+1/3+1/5+1/7+1/9+...1/99计算有什么规律 1-1/3-1/5＋1/3-1/5-1/7＋1/5-1/7-1/9……+1/2003-1/2005-1/2007 (1/2005-1)(1/2004-1)........(1/3-1)(1/2-1) 1*2*3/1+2*3*4/1+...+8*9*10/1 (1+1/2)x(1-1/2)x(1+1/3)x(1-1/3)x..........x(1+1/9)x(1-1/9)=? (1+1/2)x(1-1/2)x(1+1/3)x(1-1/3)x..........x(1+1/9)x(1-1/9)=? lim[(1-1/4)(1-1/9)...(1-1/(n+1)^2]=?