> 数学 >
1/1×2+1/2×3+1/3×4+1/4×5+...+1/39×40
人气:203 ℃ 时间:2020-01-29 06:42:51
解答
1/1×2+1/2×3+1/3×4+1/4×5+...+1/39×40
=1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/39-1/40
=1-1/40
=39/40
推荐
猜你喜欢
© 2024 79432.Com All Rights Reserved.
电脑版|手机版