a 3/1x5-7/5x9+11/13x17+19/17x21-...+2011/2009x2013=?
b
A B
x B C
__________
A B
C D E
__________
C B B B ABDE this number is ?
c
A B C D
B C D
C D
+ D
_______________
2 0 1 2 ABCD this numder is ?
d 88+1_ _+_ _8=8_ _+_ _1+88 THE NUMBER MUST BE 1/8/0
e 68-6_+_8=8_+_9-89 THE NUMBER MUST BE 1/6/8/9/0
Mathematies questions(3)
2015-04-27 1:54 am
回答 (6)
2015-04-27 11:32 pm
✔ 最佳答案
3/1x5 - 7/5x9 + 11/9x13 - 15/13x17 + ... + 2011/2009x2013= (1/2+1/10) - (1/10+1/18) + (1/18+1/26) - (1/26+1/34) + ... + (1/4018+1/4026)
= 1/2 + 1/4026
= 1012/2013
４３
ｘ ３１
－－－－－
４３
１２９
－－－－－
１３３３
１４６８
４６８
６８
８
－－－－－
２０１２
88 + 101 + 808 = 808 + 101 + 88 (many possible solutions)
68 - 68 + 18 = 88 + 19 - 89 (many possible solutions)
參考: knowledge
2015-04-27 8:36 pm
c) We start from right hand side first. D = 3 or D = 8. There are 2 possible ways.
Let D be 3. Then everything will work out fine.
If D is 3, then C must be 0. If C is 0, then B must be 0 too. If B is 0, then A must be 2. Therefore, ABCD is 2003.
For the case D = 8. It won't work out at all.
Let D be 3. Then everything will work out fine.
If D is 3, then C must be 0. If C is 0, then B must be 0 too. If B is 0, then A must be 2. Therefore, ABCD is 2003.
For the case D = 8. It won't work out at all.
2015-04-27 7:42 pm
(d) has many solutions :
88+101+808 = 808+101+88
88+111+808 = 818+101+88
88+181+808 = 888+101+88
88+111+888 = 888+111+88
...
88+101+808 = 808+101+88
88+111+808 = 818+101+88
88+181+808 = 888+101+88
88+111+888 = 888+111+88
...
2015-04-27 8:19 am
邊位都好 老師 英明～
2015-04-27 6:12 am
第一題是否打漏了？應該係
3/1x5-7/5x9+11/9x13-15/13x17+19/17x21-...+2011/2009x2013=?
3/1x5-7/5x9+11/9x13-15/13x17+19/17x21-...+2011/2009x2013=?
2015-04-27 5:57 am
Very difficult *_*
收錄日期: 2021-04-15 19:11:56
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20150426000051KK00071