2+4+6+8...........+208+210 = ?
回答 (8)
2019-06-19 7:06 pm
✔ 最佳答案
2+4+6+8...........+208+210 = ?Sol
A=2+4+6+…+206+208+210
A=210+208+206+…+6+4+2
2A=(2+210)+(4+208)+(6+2-6)+…+(206+6)+(208+4)+(210+2)
=212*(210/2)
=212*105
=22260
A=11130
or
項數=210/2=105
2+4+6+8...........+208+210
=(2+210)*105/2
=106*105
=11130
2019-06-19 7:02 pm
= 2*(1+105)*105/2
= 105*106
= 105*106
2019-06-20 4:20 am
Sn = (an² - a₁²) / 2d + (a₁ + an) / 2
= (210² - 2²) / 2·2 + (2 + 210) / 2
= 11130 #
= (210² - 2²) / 2·2 + (2 + 210) / 2
= 11130 #
2021-03-13 12:36 pm
你哋啲題目咁深㗎！😔😔😔😡🤯🤯
2020-08-28 3:24 pm
項數＝(210-2)÷2+1=105
答案＝（210＋2)x105÷2=22260
答案＝（210＋2)x105÷2=22260
2020-02-13 11:23 am
2+4+6+8...........+208+210 = ?
Sol
A=2+4+6+…+206+208+210
A=210+208+206+…+6+4+2
2A=(2+210)+(4+208)+(6+2-6)+…+(206+6)+(208+4)+(210+2)
=212*(210/2)
=212*105
=22260
A=11130
or
項數=210/2=105
2+4+6+8...........+208+210
=(2+210)*105/2
=106*105
=11130
Sol
A=2+4+6+…+206+208+210
A=210+208+206+…+6+4+2
2A=(2+210)+(4+208)+(6+2-6)+…+(206+6)+(208+4)+(210+2)
=212*(210/2)
=212*105
=22260
A=11130
or
項數=210/2=105
2+4+6+8...........+208+210
=(2+210)*105/2
=106*105
=11130
2020-01-24 9:57 pm
11130 is the answer
use畢氏定理
use畢氏定理
2019-06-20 11:09 pm
(2+210)*105/2=11130 #
收錄日期: 2021-04-11 22:54:46
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20190619105753AA2lG7t