国际顶尖MBA申请交流平台--TOPWAY MBA - Powered by Discuz! Board

标题: 同志们做提要细心呀这几道提有做错了把? [打印本页]

作者: windtalker 时间: 2003-1-14 22:24 标题: 同志们做提要细心呀这几道提有做错了把?

有个球落到地上，回弹3/4。共弹了14**厘米，问第三次落下的高度是多少 [思路]为等差数列，公差为3/4 Sn=14** 求a3 38. K=0.1-(0.1)^2，问x>0.05? 1) K>0.009/x 2) K<0.0009/x 我选D K=0.1-(0.1)^2=0.1-0.01=0.09 1)K>0.009/x x>0.009/k=0.1 X>0.1>0.05所以(1)足够 2) K<0.0009/x x<0.0009/k x<0.0009/0.09=0.01 x<0.01<0.05所以(2)足够回答 ANS: D [确认] D 应该选B,注意利用条件1时不要忽视X小于零的情况因为题目中并未规定X大于 60 cars, either full size or midsize or compact. 10 are red, 19 are blue, How many cars are full size? 1) No red or blue cars are full size 2) The number of full size car is greater than the sum of mid size and compact cars 我选C 由以下表来表达 Fullsize, F midsize, M compact, C subtotal White, W 31 0 0 31 Red, R 0 10 Blue, B 0 19 Subtotal 31 60 因RF and BF =0 (given) 所以 M+C=or at least=10+19 由1strow, F=<31 F+M+C=60 F must be either 30, or 31 题干给 F>M+C 所以F不能是30,只能是31, M+C=29 [确认] C ?F凭什么不能等于30?试想因为M+C>=29, 在M+C=30的情况下F=30,所以此题应选E 40. 0.00625 is between 1/10^(n-1) and 1/10^n, what is the value of n? Ans: n=3 [确认] n=3 不对把:--是我马虎还是您马虎哇,明明应该N-1=3,N=4

作者: 卧室春竹 时间: 2003-1-14 23:32

O.00625 那么肯定是 0.001<0.00625<0.01 0.0001=10^-3 0.01=10^-2 1/10^N-1>1/10^N 所以 N=3 您可能看错关系了.... 应该N-1是2 如果 N=4 那么 0.00625 就在 0.0001 0.001 之间了吧？！这样不成立了...

作者: VICTOR_JZG 时间: 2003-1-15 10:57 标题: Re-check!

以下是引用windtalker在2003-1-14 22:24:08的发言： 1. 有个球落到地上，回弹3/4。共弹了14**厘米，问第三次落下的高度是多少 [思路]为等差数列，公差为3/4 Sn=14** 求a3 2. 38. K=0.1-(0.1)^2，问x>0.05? 1) K>0.009/x 2) K<0.0009/x 我选D K=0.1-(0.1)^2=0.1-0.01=0.09 1)K>0.009/x x>0.009/k=0.1 X>0.1>0.05所以(1)足够 2) K<0.0009/x x<0.0009/k x<0.0009/0.09=0.01 x<0.01<0.05所以(2)足够回答 ANS: D [确认] D 应该选B,注意利用条件1时不要忽视X小于零的情况因为题目中并未规定X大于 3. 60 cars, either full size or midsize or compact. 10 are red, 19 are blue, How many cars are full size? 1) No red or blue cars are full size 2) The number of full size car is greater than the sum of mid size and compact cars 我选C 由以下表来表达 Fullsize, F midsize, M compact, C subtotal White, W 31 0 0 31 Red, R 0 10 Blue, B 0 19 Subtotal 31 60 因RF and BF =0 (given) 所以 M+C=or at least=10+19 由1strow, F=<31 F+M+C=60 F must be either 30, or 31 题干给 F>M+C 所以F不能是30,只能是31, M+C=29 [确认] C ?F凭什么不能等于30?试想因为M+C>=29, 在M+C=30的情况下F=30,所以此题应选E 4. 40. 0.00625 is between 1/10^(n-1) and 1/10^n, what is the value of n? Ans: n=3 [确认] n=3 不对把:--是我马虎还是您马虎哇,明明应该N-1=3,N=4

1. Yeah, you are right. If the titled question means bounce once and the total is 14**cm, then, we can presume the first drop is X, then we get X*(1+3/4)=14**cm. Then, the final answer should be like this:9*(14**)/28 2.Agree with you! I chose B. But I dare not to paste my choice. Hehehe.. 3.I think it should be C. "F凭什么不能等于30?试想因为M+C>=29, 在M+C=30的情况下F=30" But the condition No. 2 is "The number of full size car [U]is greater than[/U] the sum of mid size and compact cars". So, combining 1 and 2 together, the answer is 31. That's why I chose C. 4. I think "是您马虎哇": 0.00625=5/800=1/160."between 1/10^(n-1) and 1/10^n", then n-1=2, n=3. Agree?

作者: windtalker 时间: 2003-1-16 13:05 标题: Sorry, 是我马虎

！

作者: hilisa 时间: 2003-1-17 11:48

有个球落到地上，回弹3/4。共弹了14**厘米，问第三次落下的高度是多少
[思路]为等差数列，公差为3/4
Sn=14** 求a3
---------------------------------------
我怎么觉得这样做，大家看看对不对：
设第一次落下x厘米，则14** = x + x*3/4 + x*3/4 + x*(3/4)^2
算出x, 则最终答案是x*(3/4)^2
解题思路是： 14** = 第一次落下 + 第一次弹起 + 第二次落下 + 第二次弹起
不知对否？

欢迎光临国际顶尖MBA申请交流平台--TOPWAY MBA (http://forum.topway.org/)

Powered by Discuz! 7.2