Sandy Zhu
1.8K posts
Sandy Zhu retweetledi
最近，澳大利亚一个叫塔斯马尼亚岛火了，原因是台湾网友准备众筹把岛买下，然后把台湾2千多万人口迁过去，台湾岛还给大陆，这真是一个两全其美的方案☺️😉😇
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剑桥的女留子，为啥我看了后觉得一言难尽呢？我以前留学都是上课做实验做作业准备考试做group project写paper循环反复，可她们这，而且这口语。。。
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🔥重磅！Tesla Semi正式量产，第一辆车已下线！
4680电池+800V架构，能耗从2降至1.7kWh/英里，运营成本仅柴油卡车的1/2至1/4。10万英里可省5-7万美元，2年内回本！
更炸裂的是：搭配Robotaxi全自动驾驶后，卡车可24小时运行，利用率提升5倍，运输成本从1.6-2美元/英里暴降至0.4-0.5美元！食品等商品运输成本占总成本10-20%，全面普及后将降至1-2%，相当于给整个经济体一次超级减税！番茄等商品落地成本有望砍掉2/3！
这不是卡车，是生产力核弹！
#TeslaSemi #Robotaxi #FSD
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是你也会这么选吗，卖掉山东137平的大房子换成上海35平的老破小，掏空自己的钱包积蓄加父母的资助也要拥有一套上海属于自己的蜗居？
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@dlw20202020 现实问题是，如果不雇印度人就没有足够的利润，甚至可能竞争不过星巴克。而且Tims也早已不是加拿大公司，最大股东好像是一家巴西的公司。
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冷知识。
1. 付鹏去年比特币 12 万的时候，就进入币圈卖过课，年费 1598 人民币。
2. 然而他在 24 年，自己的黄金付费课表示，看空比特币、黄金，当时黄金 2300，比特币 6 万，随即很多订阅者，闹过退款。
3. 同年底，老哥因发表长篇看空中国经济，他的账号被冻结，结果 2 年了，经济并没崩，中产也没完蛋。
4. 在这件事的几个月后，老哥辞去东北证券首席经济学家职务，声称是因病原因。
以上在联合早报、雅虎财经、彭博社，都有历史。
祝他好运。
Meguro-ku, Tokyo 🇯🇵 中文
@LaurenceMister 那我就不看了，原本还打算致敬一下。被你这么一说，算了吧。对现在的电影真的是没脾气了！感觉钱都花在了宣传上，就没用在好好拍片上！
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想让币圈的人乖乖的叫老师：要么你实盘赚了很多钱，大家有目共睹；要么你分析行情分析的确实很牛逼，长期看下来正确率很高；要么你真能带人抄底逃顶经过了时间的验证。
如果只顶着一个“经济学家”的名头就在这里耍大牌，呵呵，对不起，这个圈子不会买你的单，你还是回私人银行、基金装逼去吧。
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@danielfoch 5minutes charge for 400-600km range, I am buying a bomb!
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中国业内知情人士发布视频透露现在大家吃到的面粉，某种意义上叫做面味粉而不是面粉！它是工业化流水线上最未端的产品，工业化面粉的精华被抽取，最有营养的麦心和胚芽被提取高价售卖；边角料加工剩下20%到30%的麸皮制成普通面粉，用增白剂进行美白、提精剂增精、防腐剂续命、滑石粉光滑又锃亮；营养严重流失，失去了小麦最珍贵的营养成分。
为什么要选择传统面粉，因为它保留了完整麦粒所有的营养不含工业提取和化学添加剂，每一口都是实实在在粮食的精华。
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这个国家以及很多人欠拜登一个道歉。拜登肯定不完美，但他是一个及格的政客以及总统。
另一个嘛，别说总统了，连做人都不配。🤮🤮🤮
Adam 🇬🇧🇺🇦@Adam65207241
川普又在4月23日的直播会议中睡着了。 如果乔·拜登这么做，媒体会把它当成国家紧急事件，连续一周进行铺天盖地的恐慌报道。 但当川普这么做时，川粉就视而不见，因为这场闹剧能维持他们的收视率和钱包鼓鼓的。
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Sandy Zhu retweetledi
An MIT professor taught the same math course for 62 years, and the day he retired, students from every country on earth showed up online to watch him give his final lecture.
I opened the playlist at 2am and ended up watching three of them back to back.
His name is Gilbert Strang. The course is MIT 18.06 Linear Algebra.
Every machine learning engineer, every data scientist, every quant, every self-taught programmer who actually understands how AI works learned the math from this one man. Most of them never set foot on MIT's campus. They just opened a free playlist on YouTube and let him teach.
Here's the story almost nobody tells you.
Strang joined the MIT math faculty in 1962. He retired in 2023. That is 61 years of standing at the same chalkboard teaching the same subject to 18-year-olds.
The interesting part is what he did when MIT launched OpenCourseWare in 2002. Most professors were skeptical. They worried that putting their lectures online would make their classrooms irrelevant. Strang did not hesitate. He said his life's mission was to open mathematics to students everywhere. He filmed every lecture and gave it away.
The decision quietly changed how the world learns math.
For decades linear algebra was taught the wrong way. Professors started with abstract vector spaces and proofs about field axioms. Students drowned in the abstraction. Most never recovered. They walked out believing they were bad at math when they had simply been taught in an order that nobody's brain is built to absorb.
Strang inverted the entire curriculum.
He started with matrix multiplication. Something you can write down on paper. Something you can compute by hand. Something you can see. Then he showed his students that everything else in linear algebra eigenvectors, singular value decomposition, orthogonality, the four fundamental subspaces was just a different lens for understanding what the matrix was actually doing under the hood.
His rule was strict. If a student could not explain a concept using a concrete 3 by 3 example, that student did not actually understand the concept yet. The abstraction was supposed to come last, not first. The intuition was the foundation. The proofs were just confirmation that the intuition was correct.
The second thing Strang changed was the classroom itself. He said please and thank you to his students. Every single lecture. He paused mid-derivation to ask "am I OK?" to check if anyone was lost. He never used the word "obviously" or "trivially" because he knew exactly what those words do to a student who is one step behind. He treated 19-year-olds learning math for the first time the way he treated his own colleagues. With patience. With respect. With the assumption that they belonged in the room.
For 62 years.
The result is something that has never happened in the history of education. A single math professor became the default teacher of his subject for the entire planet.
Universities in India, China, Brazil, Nigeria, every country with a computer science department, started telling their own students to just watch Strang's lectures. The University of Illinois revised its linear algebra course to do almost no in-person lecturing. The reason was honest. The professor said they could not compete with the videos.
His final lecture was in May 2023.
The auditorium was packed with students who had never met him before. He walked to the chalkboard, taught for an hour, and at the end the entire room stood and applauded. He looked confused for a moment, like he genuinely did not understand why they were cheering. Then he smiled and waved them off and walked out.
His written comment under the YouTube video of that final lecture was four sentences long. He said teaching had been a wonderful life. He said he was grateful to everyone who saw the importance of linear algebra. He said the movement of teaching it well would continue because it was right.
That was it. No book promotion. No farewell speech. No legacy management.
The man whose teaching is the foundation of modern AI just thanked the audience and went home.
20 million views. Zero ego. The entire engine of the AI revolution sits on top of math that millions of people learned for free from one quiet professor in Cambridge.
The course is still on MIT OpenCourseWare. Every lecture, every problem set, every exam, every solution. Free.
The most important math course of the 21st century is sitting one click away from you. Most people will never open it.
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