设原式的和为S,再把原式乘以1/2得:
1/2S=1/2*(1/3+1/6+1/10+1/15+……+1/55)
=1/6+1/12+1/20+1/30+1/42+……+1/110
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+……+1/10-1/11
=1/2-1/11
=9/22
两边乘以2得:S=18/22
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/50+1/55=?
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/50+1/55=?
用裂项法做
用裂项法做
数学人气:820 ℃时间:2019-09-22 03:01:34
优质解答
我来回答
类似推荐
猜你喜欢
- 1we don't need to finish this fork at once=It is_______ _______ us to finish this work at once
- 2The light in Mrs White’s bedroom is on.She ____ be at home now.填must还是 can
- 3关于x,y的一元一次方程组3x+7y=k 2x+3y=2的解都是正数,求k的值
- 4用滴管吸取溶液或压放溶液时,要缓压胶头,避免用力过大损坏胶头或使试剂()
- 5一栋楼房每上一层走18个台阶、小红家要上162个台阶、住在第几层?
- 6The robber had escaped and was nowhere to be found when the police ____
- 7连词成句 play after guitar i often the dinner
- 8小学五年级上册英语朗读单词
- 9已知:如图,在△ABC中,点D、E、F分别在AC、AB、BC边上,且四边形CDEF是正方形,AC=3,BC=2,求△ADE、△EFB、△ACB的周长之比和面积之比.
- 10学校食堂计划m天用煤a吨,要使存煤比预定多用n天,则每天应节约用煤几吨?