fun

Weekly cycle of alivelearn.net traffic

Number of people visiting this blog fluctuates periodically with period 1 week. Basically on weekends few people visit.
Xu Cui
5 sec read

Solution of Basel problem by Euler (from wikipedia)

Basel problem: find the exact value of $$1+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+… = ?$$ Solution: We have by Taylor expansion: $$\sin(x)=x-\frac{x^3}{3!}+\frac{x^5}{5!}-\frac{x^7}{7!}+…$$ Dividing through x we have, $$\frac{\sin(x)}{x}=1-\frac{x^2}{3!}+\frac{x^4}{5!}-\frac{x^6}{7!}+…$$ Note,...
Xu Cui
26 sec read

i to i

What is the value of $$i^i$$ \(i\) being the imagery unit. This beautiful number indeed equals to $$i^i=e^{-\pi/2}=0.2079…$$
Xu Cui
4 sec read

Why is temporal lobe called “temporal”

The name of “temporal lobe” follows “temporal bone”. But why “temporal”? The reason is that when people get old, the first region in the...
Xu Cui
12 sec read

no tissue paper

Original Video– More videos at TinyPic
Xu Cui
1 sec read

两个奇怪的成语:卧槽泥马,马勒戈壁

卧槽泥马:   ⑴形容识人不明.表示明明其能力不足.但上位者因为种种原因或糊涂.任其肆意妄为.   ⑵形容虚有其表,窃居名位者.表示即使给某人相应的地位.但其能力不足是无法改变的.(等同于烂泥扶不上墙.沐猴而冠)   ⑶形容模仿不到家,反而不伦不类.   典故:出自《战国策.楚策四》   伯乐多良马.其有邻亚犁.曾与人言.”我亦善识马.有一骏马.伯乐不及.”人皆疑.欲观之.亚犁恐.乃以草泥置一卧马于槽中.众人视之笑其蠢.皆曰:”此何良驹.卧槽泥马尔.”   下面给出三个词义的例句:   1、红鸟这厮也能当上十二骑士,卧槽泥马啊;   2、阿斗烂泥扶不上墙,即使上将潘凤在身边也不能稳坐江山,卧槽泥马呀;   3、不会做就别做,PS个老虎照片也敢拿出来,真是卧槽泥马。   此外,象棋中有一类残局叫做“泥马残局”,其中也有以“卧槽泥马”为名的杀法。此类残局来源于“泥马渡康王”的传奇故事,摘录如下。   夹江卧槽泥马渡康王 ……        典出《战国策.楚策四》?翻烂了《战国策》也只有找到这段和马有关:   “汗明见春申君,候问三月,而后得见。谈卒,春申君大悦之。……汗明曰:“君亦闻骥乎?夫骥之齿至矣,服盐车而上太行。蹄申膝折,尾湛溃,漉汁洒地,白汗交流,中阪迁延,负辕不能上。伯乐遭之,下车攀而哭之,解衣以之。骥于是而喷,仰而鸣,声达于天,若出金石声者,何也?彼见伯乐之知己也。……” 另外,我想“卧槽泥马”都是成语,那“马勒戈壁”必定也是成语了,经过我多日的收集资料和研究,终于应正了我的想法。如下资料: 马勒戈壁:   词义:比喻天下太平,不再用兵。现形容思想麻痹。   词音:mǎ le ge bi   出处:《尚书.武成》:“王来自商,至于丰,乃偃武修文,归马于戈壁之阳,放牛于桃林之野,示天下弗服。”...
Xu Cui
4 sec read

I’m in newspaper :)

Check out http://www.photofunia.com/. It’s fun.
Xu Cui
1 sec read