观察下列等式: 1⼀1X2+1⼀2X3+1⼀3X4=1-1⼀2+1⼀2-1⼀3+1⼀3-1⼀4=1-1⼀4=3⼀4

2024-12-26 23:30:31
推荐回答(2个)
回答1:

观察下列等式:
1/1X2+1/2X3+1/3X4
=1-1/2+1/2-1/3+1/3-1/4
=1-1/4
=3/4
(1)直接写出下列各式的计算结果:
1/1X2+1/2X3+1/3X4+...+1/2006X2007
=1-1/2+1/2-1/3+1/3-1/4+……+1/2006-1/2007
=1-1/2007
=2006/2007

(2)探究并计算:
1/2X4+1/4X6+1/6X8+...+1/2006X2008
=1/2×(1/2-1/4+1/4-1/6+1/6-1/8+……+1/2006-1/2008)
=1/2×(1-1/2008)
=1/2×2007/2008
=2007/4016

回答2:

(1)直接写出下列各式的计算结果:
1/1X2+1/2X3+1/3X4+...+1/2006X2007=1-1/2+1/2-1/3+1/3-1/4+...+1/2006-1/2007=1-1/2007=2006/2007
(2)探究并计算:
1/2X4+1/4X6+1/6X8+...+1/2006X2008
=1/4(1/1x2+1/2x3+...+1/1003x1004)=1/4*(1-1/1004)=1003/4016