1⼀1×3 1⼀3×5 ……1⼀2013×2015等于多少

2025-06-22 01:53:19
推荐回答(1个)
回答1:

解:1/1×3+1/3×5+1/5×7+.+1/2013×2015
=1/2×(1-1/3)+1/2×(1/3-1/5)+…+1/2×(1/2013-1/2015)
=1/2×(1-1/3+1/3-1/5+.+1/2013-1/2015)
=1/2×(1-1/2015)
=1/2×2014/2015
=1007/2015