(1/2+1/3+...+1/2014)(1+1/2+1/3...+1/2013)-(1+1/2+1/3+...+1/2
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/17 04:04:01
(1/2+1/3+...+1/2014)(1+1/2+1/3...+1/2013)-(1+1/2+1/3+...+1/2014)(1/2+1/3+...+1/2013)
七年级新观察“专题 有理数四则混合运算”T9
七年级新观察“专题 有理数四则混合运算”T9
答:
设a=1/2+1/3+...+1/2014,b=1/2+1/3...+1/2013
(1/2+1/3+...+1/2014)(1+1/2+1/3...+1/2013)-(1+1/2+1/3+...+1/2014)(1/2+1/3+...+1/2013)
=a(1+b)-(1+a)b
=a+ab-b-ab
=a-b
=1/2014
设a=1/2+1/3+...+1/2014,b=1/2+1/3...+1/2013
(1/2+1/3+...+1/2014)(1+1/2+1/3...+1/2013)-(1+1/2+1/3+...+1/2014)(1/2+1/3+...+1/2013)
=a(1+b)-(1+a)b
=a+ab-b-ab
=a-b
=1/2014
(1/2+1/3+...+1/2014)(1+1/2+1/3...+1/2013)-(1+1/2+1/3+...+1/2
计算:(1/2015-1)(1/2014-1)(1/2013-1)...(1/3-1)(1/2-1)
|1\2-1| + |1\3-1\2| + |1\4-1\3| +.+ |1\2014-1\2013|
|1/2-1|+|1/3-1/2|+|1/4-1/3|+.+|1/2014-1/2013|
|1/2-1|+|1/3-1/2|+|1/4-1/3|+...+|1/2014-2013|
计算(1-1/2)(1/3-1)(1-1/4)(1/5-1)...(1/2013-1)(1-1/2014)
(1/2014-1)(1/2013-1)(1-2012-1)...(1/3-1)(1/2-1)
(2014/1-1)(2013/1-1)(2012/1-1)乘以...乘以(3/1-1)乘以(2/1-1)
(1/2014-1)×(1/2013-1)×(1/2012-1)…(1/3-1)(1/2-1)
|2/1-1|+|3/1-2/1|+.+|2014/1-2013/1|这道数学题怎么做?
(2013/1-1)(2012/1-1)(2011/1-1).(3/1-1)(2/1-1)
计算:1/(1*3)+1/(2*4)+1/(3*5)+...+1/(2011*2013)+1/(2012 *2014)