1.等差数列中,若前四项和为21.末四项和为67,前n项和为286,则该数列的项数是_____?2.数列{an}满足:a1=1,且对任意的m,n∈N*都有:a(m+n)=am+an +mn,则1/a1+1/a2+1/a3+……+1/an=_______?额.第二个题里面字母
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/31 16:52:56
![1.等差数列中,若前四项和为21.末四项和为67,前n项和为286,则该数列的项数是_____?2.数列{an}满足:a1=1,且对任意的m,n∈N*都有:a(m+n)=am+an +mn,则1/a1+1/a2+1/a3+……+1/an=_______?额.第二个题里面字母](/uploads/image/z/2084721-33-1.jpg?t=1.%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%E4%B8%AD%2C%E8%8B%A5%E5%89%8D%E5%9B%9B%E9%A1%B9%E5%92%8C%E4%B8%BA21.%E6%9C%AB%E5%9B%9B%E9%A1%B9%E5%92%8C%E4%B8%BA67%2C%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BA286%2C%E5%88%99%E8%AF%A5%E6%95%B0%E5%88%97%E7%9A%84%E9%A1%B9%E6%95%B0%E6%98%AF_____%3F2.%E6%95%B0%E5%88%97%EF%BD%9Ban%EF%BD%9D%E6%BB%A1%E8%B6%B3%EF%BC%9Aa1%3D1%2C%E4%B8%94%E5%AF%B9%E4%BB%BB%E6%84%8F%E7%9A%84m%2Cn%E2%88%88N%2A%E9%83%BD%E6%9C%89%EF%BC%9Aa%28m%2Bn%29%3Dam%2Ban+%2Bmn%2C%E5%88%991%2Fa1%2B1%2Fa2%2B1%2Fa3%2B%E2%80%A6%E2%80%A6%2B1%2Fan%3D_______%3F%E9%A2%9D.%E7%AC%AC%E4%BA%8C%E4%B8%AA%E9%A2%98%E9%87%8C%E9%9D%A2%E5%AD%97%E6%AF%8D)
xTKR@Ռ)d(e)*aC`clB0,](HZq(beJ5_w\Y@5ۻ٪vСmZR!F&;>mI!oN_^G2pkV-geRwˤFe| [7L)