1⼀3+1⼀8+1⼀15+1⼀24+...+1⼀n(n+1)怎么求

2024-12-23 07:50:22
推荐回答(2个)
回答1:

题目写错,应该是:
1/3+1/8+1/15+1/24+...+1/n(n+2)
2/n(n+2)=1/n-1/(n+2)
1/3+1/8+1/15+1/24+...+1/n(n+2)
={[1-1/3]+[1/3-1/5]+[1/5-1/7]+……+[1/n-1/(n+2)]/2
=[1-1/(n+2)]/2=(n+1)/(2n+4)

回答2:

1/3+1/8+1/15+1/24+...+1/n(n+2)=[1-1/3]+[1/3-1/5]+[1/5-1/7]+……+[1/n-1/(n+2)]/2 =[1-1/(n+2)]/2=(n+1)/(2n+4)