一站崩，放狗

athenaeee

630，数学49，
数学，一个地方有种树，标号201-740（我记得是一共540颗树），然后这些树中，松树的号码是以7、6、5、4开头或者是以2、3、4、5结尾，问随便抽出来一个树，注意，抽出来不是松树的概率。构筑选的25%。


坐稳，
一个人建议convention centre 旁边开个豪华宾馆，为了提升城市税收和增加会议中心attandance（这个会议中心目前book rate只有50%）. 物理假设，没有证据表明会有人住新的hotel,更不能为城市带来多余税收了。

语文，
四篇阅读都是jj里面的，考之前都看了，依然只有630，红移，女性golden time那个， hotel room,grass shrub那一篇。

JOICHI

楼主辛苦。
请问你数学遇到JJ 多吗？
月度，红移 是哪一篇呀？15/7号的吗？

billyisfragile!

一个地方有种树，标号201-740（我记得是一共540颗树），然后这些树中，松树的号码是以7、6、5、4开头或者是以2、3、4、5结尾，问随便抽出来一个树，注意，抽出来不是松树的概率。构筑选的25%。

2019-7-18 23:12:27

1. (最后一题，知道方法没来得及算完，所以印象深刻。）
PS: 种树给每棵树编号，号码是三位数，从201到740。其中pine tree的百位可以是 4，5，6 or 7,  个位可以是 2，3，4 or 5. 随机选一棵树， what is the probability of the tree NOT being pine tree?

2017-9-18 22:03:58
有一堆树，标记为201-740， 里面编号2345开头同时2345结尾的树为pine trees，问不是pine tree的约占总数多少？   

2017-9-18 22:29:02
=1-P（是pine trees的概率）=1-4*4*10/(740-201+1)=1-8/27=19/27

2012-8-29 12:49:04

201到740,4到7后面位数也是4四个数不是5个，最后是0.75确定,

2012-8-21 20:22:22

算树那道，编号是201到740，4567开头6789结束的是一种树，问其它树的比例。注意从700~740只有16棵。     

athenaeee

JOICHI 发表于 2019-9-3 14:33
楼主辛苦。
请问你数学遇到JJ 多吗？
月度，红移 是哪一篇呀？15/7号的吗？ ...

前十来个提都没有，我还以为换哭了，之后有了，还行，起码十个左右。
红移你看目前阅读的jj，red shift那一篇

billyisfragile!

athenaeee 发表于 2019-9-3 17:08
前十来个提都没有，我还以为换哭了，之后有了，还行，起码十个左右。
红移你看目前阅读的jj，red shift那 ...

是原文吗？

JOURNAL ARTICLE
The Large-Scale Streaming of Galaxies
Alan Dressler
Scientific American
Vol. 257, No. 3 (SEPTEMBER 1987), pp. 46-55
Published by: Scientific American, a division of Nature America, Inc.
Stable URL: http://www.jstor.org/stable/24979477
Page Count: 10

The origin and fate of the universe are imprinted on the motions of its constituents. In the early 1920's, soon after the discovery that our own galaxy is one of billions, it was shown that distant galaxies are receding in all directions. It was evident that the universe is expanding and the galaxies are being swept apart, carried by a uniformly enlarging fabric of spacetime.

galaxy测量，说根据galaxy的发光偏红可以推测出宇宙是向外扩张的，并且某些科学家还发现了扩张的速度和路程的关系什么的，（有题目考到第二段的作用，楼主选的是，给出证据解释上面提到的一种理论）但是最后提到不知道宇宙的终结(the other end of time)是什么，有可能星球的万有引力会抵消向外扩张的力量，甚至倒转。（有考到题目，总之知道原理就能选对

More recently it has become clear that galaxies are not at rest with respect to this unfolding fabric. They show motions of their own, which offer insight into the texture of the cosmos: the extent of its fluctuations in mass density. What is already known of the motions suggests that matter is clumped together on unimaginably large scales, reflecting poorly understood events in the early universe. The motions may also answer a question about the other end of time: Will the expansion of the universe continue, or will the force of gravity ultimately stop the expansion or even reverse it, causing the universe to recollapse into primordial density? Several groups, including a group to which I belong, are engaged in mapping the pattern and scale of the cosmic flow.

p2:兩學者引用都卜勒效應裡的紅移現象（有題highlight這段問作用）

第二段是讲，两位 仁兄S和M通过实验发现了red shift，然后spectralline，怎么怎么的，没怎么看懂

The cosmological importance of galactic motions was established in  the early part of this century, when the American astronomers Edwin P. Hubble and V. M. Slipher began measuring displacements of spectral lines in the light from other galaxies. Such shifts reflect the Doppler effect: the change in the wavelength of radiation or sound that results from motion of the source with respect to the observer. Most of the galaxies showed a red shift, meaning that the lines were displaced toward the red, or longer-wavelength, side of the spectrum. A red shift indicates motion away from the observer.

Sixty years later it is difficult to appreciate how radical suggestions that other galaxies are receding in all directions sounded when they were made in the early 1920's. They represented a change in world view in every way as fundamental as the Copernican revolution; the notion of a static universe was by then as well established as the geocentric universe had been in the 15th century.  Indeed, Hubble himself at first interpreted his data as evidence for a motionless universe. He believed he had confirmed a theoretical analysis by the Dutch mathematician Willem de Sitter, who had found a static solution to Einstein's equations of general relativity. By including a term that described a dilation of time with increasing distance, the analysis gave rise to red shifts that increased for more distant galaxies, even without relative motion.

第三段是讲在1930年后，又发现了Huber Law，什么velocity equal to什么的，证明galaxies locomotion是uniform的
实验：2 个实验证明宇宙是扩张的观点；射线的 rate 测试出距离；
但是东西逃逸不出去后，就又回到了奇点，回到了 Big Bang；

By the late 1930's, however, the idea that the universe is expanding had seized nearly everyone, even the recalcitrant Hubble, and measuring the red shifts of galaxies at ever greater distances was the order of the day. When the red shifts of remote galaxies were correlated with their distances, estimated from their apparent brightnesses, a relation emerged that was as simple as one could have hoped: the recession velocity of a galaxy equals its distance multiplied by a constant. The implication of this linear relation, known as the Hubble law, was clear: the expansion of the universe is uniform. A being in a galaxy billions of light¬ years away would see the same relation between distance and red shift in surrounding galaxies as is seen from the Milky Way. By the 1970's it was generally accepted that the Hubble law has a second implication: the observed expansion of the universe was unleashed some 15 billion years ago in an explosive creation event, the big bang.

JOICHI

谢谢你，希望你下次过700，加油。

athenaeee

bzy! 发表于 2019-9-3 21:50
是原文吗？

JOURNAL ARTICLE

额。。。想起一体第一题，说重力的作用，四段从头找了半天，结果在文章最后一句。大概是问作者suggest重力作用导致啥。构筑看最后那句说的是重力导致这种宇宙扩张会停止。

神风特攻

请问楼主还记得CR的Jj吗，多谢了

athenaeee

神风特攻 发表于 2019-9-4 12:01
请问楼主还记得CR的Jj吗，多谢了

不行啦，主要是水平不咋地啊，逻辑链条也不清晰

davidxmz

bzy! 发表于 2019-9-3 15:11
2019-7-18 23:12:27

1. (最后一题，知道方法没来得及算完，所以印象深刻。）

好像跟你考古的题干条件不一样？
LZ这道是头or尾满足编号，这样算出来好像不是25%、、、