1/11X13x15+1/13x15x17+......+1/29x31x33

显示全部楼层 · 2019-9-20 18:57:26

你好！4(1/(31*33*13)=20/13x15x17+1/11X13x15+1/......+1/4(1/11X13-1/31x33)=1/11X13-1/..+1/4(1/29X31-1/31x33)=1/29x31x33=1/4(3*31-13)/13x15)+1/4(1/13x15-1/15x17)+..;13299答：最后等于20/希望对你有所帮助，望采纳。

千问 · 2019-9-20 18:57:26

1/11X13x15+1/13x15x17+......+1/29x31x33= 1/4(1/11X13 - 1/13x15) + 1/4(1/13x15 - 1/15x17)+ ....+ 1/4(1/29X31 - 1/31x33) = 1/4 (1/11X13 - 1/31x33) = 1/4 (3*31-13)/(31*33*13) = 20/13299答：最后等于20/13299

千问 · 2019-9-20 18:57:26

= 1/4(1/11X13 - 1/13x15) +1/4(1/13x15 - 1/15x17)+ ....+ 1/4(1/29X31 - 1/31x33)= 1/4 (1/11X13 - 1/31x33)= 1/4 (3*31-13)/(31*33*13)= 20/13299