早教吧 育儿知识 作业答案 考试题库 百科 知识分享

求1\1X2+1\2X3+1\3X4+1\4X5.+1\2009X2010的值,请帮我解答,抱歉,刚才那道题写错了,应该是1\1X2+1\2X3+1\4X5+1\6X7+...1\2009X2010,实在是sorry,

题目详情
求1\1X2+1\2X3+1\3X4+1\4X5.+1\2009X2010的值,请帮我解答,
抱歉,刚才那道题写错了,应该是1\1X2+1\2X3+1\4X5+1\6X7+...1\2009X2010,实在是sorry,
▼优质解答
答案和解析
1\1X2+1\2X3+1\3X4+1\4X5.+1\2009X2010
=1-1/2+1/2-1/3+……+1/2009-1/2010
=1-1/2010
=2009/2010