求a=(1⼀2+1⼀3+1⼀4+1⼀5+1⼀6+1⼀7+1⼀8+1⼀9)*15⼀22的整数部分

2024-12-28 07:11:12
推荐回答(1个)
回答1:

因为:1/a+1/b=(a+b)/(a*b)
所以:a=101/84,其整数部份就是1
=[(1/2+1/9)+(1/5+1/6)+(1/3+1/8)+(1/4+1/7)]*15/22
=11[(1/18+1/30)+(1/24+1/28)]*15/22
=11*48[1/(18*30)+1/(24*28)]*15/22
=24*15*[1/(18*30)]+24*15*[1/(24*28)]
=2/3+15/28
=101/84