探究并计算

来源:百度知道 编辑:UC知道 时间:2024/04/28 08:13:20
1/(2×4)+1/(4×6)+1/(6×8)+……+1/(2006×2008)

1/(2×4)+1/(4×6)+1/(6×8)+……+1/(2006×2008)
=1/2*(1/2-1/4)+1/2*(1/4-1/6)+1/2*(1/6-1/8)+......+1/2*(1/2006-2008)
=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+......+1/2006-1/2008)
=1/2*(1/2-1/2008)
=1/2*1003/2008
=1003/4016

1/(2×4)+1/(4×6)+1/(6×8)+……+1/(2006×2008)
=1/2*(1/2-1/4)+1/2*(1/4-1/6)+1/2*(1/6-1/8)+......+1/2*(1/2006-2008)
=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+......+1/2006-1/2008)
=1/2*(1/2-1/2008)
=1/2*1003/2008
=1003/4016
答案是1003/4016

原式等与1/2*(1/2-1/4)+1/2*(1/4-1/6)+1/2*(1/6-1/8)+......+1/2*(1/2006-2008)
=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+......+1/2006-1/2008)
=1/2*(1/2-1/2008)
=1/2*1003/2008
=1003/4016

原式=1/2(1/2-1/4+1/4-1/6+1/6……-1/2006+1/2006-1/2008)
=1/2(1/2-1/2008)
=1/2*(1003/2008)
=1003/4016