快点,急啊
1个回答
2014-10-12
展开全部
规律好找,化简难。
假如题目改成:1/(2+√2)+1/(3√2+2√3)+1/(4√3+3√4)+……+1/(25√24+24√25)倒好办。
1/(2+√2)=(2-√2)/2=1-√2/2
1/(3√2+2√3)=(3√2-2√3)/6=√2/2-√3/3
......
1/(25√24+24√25)=(25√24-24√25)/(25×24)=√24/24-√25/25)
1/(2+√2)+1/(3√2+2√3)+1/(4√3+3√4)+……+1/(25√24+24√25)
=1-√25/25
=4/5
假如题目改成:1/(2+√2)+1/(3√2+2√3)+1/(4√3+3√4)+……+1/(25√24+24√25)倒好办。
1/(2+√2)=(2-√2)/2=1-√2/2
1/(3√2+2√3)=(3√2-2√3)/6=√2/2-√3/3
......
1/(25√24+24√25)=(25√24-24√25)/(25×24)=√24/24-√25/25)
1/(2+√2)+1/(3√2+2√3)+1/(4√3+3√4)+……+1/(25√24+24√25)
=1-√25/25
=4/5
追问
看不懂
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询