ai32no8
幼苗
共回答了2个问题 举报
原式=(1-1/2)X(1+1/2)X(1-1/3)X(1+1/3)X(1-1/4)X(1+1/4).......(1-1/2010)X(1+1/2010)
=(1-1/2)X(1-1/3)X(1-1/4).....(1-1/2010)X(1+1/2)X(1+1/3)X(1+1/4).......(1+1/2010)
=1/2X2/3X3/4X4/5......X2009/2010X3/2X4/3X5/4.......X2011/2010
=1/2010X2011/2
=2011/4020
1年前
2