规律探索: 1⼀1x2=1⼀1-1⼀2;1⼀2x3=?-?;1⼀3x4=?-?;1⼀n(n+1)=?-? 根据以上规律计算:1⼀1x2+1⼀2x3+...1⼀n(n+1)

要填?号内的数
2024-11-06 22:22:36
推荐回答(2个)
回答1:

1/1*2=1/1-1/2;
1/2*3=1/2-1/3
1/3*4=1/3-1/4
...
1/n(n+1)=1/n -1/(n+1)

1/1*2+1/2*3+1/3*4+...+1/n(n+1)
=(1/1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/(n-1)-1/n)+(1/n -1/(n+1))
=1-1/(n+1)

回答2:

1/1x2+1/2x3+...1/n(n+1)
=(1/1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/n-1/(n+1))
=1/1-1/(n+1)
=n/(n+1)