跟讀練習: Essence of linear algebra preview - 通過影片學習英語口語

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Hey everyone!
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So, I'm pretty excited about the next sequence of videos that I'm doing.
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They'll be about linear algebra, which as a lot of you know, is one of those subjects that's required knowledge for just about any technical discipline, but it's also, I've noticed,
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generally poorly understood by students taking it for the first time time.
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A student might go through a class and learn how to compute lots of things, like matrix multiplication, or the determinant, or cross products which use the determinant,
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or eigenvalues, but they might come out without really understanding why matrix multiplication is defined the way that it is,
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why the cross product has anything to do with the determinant, or what an eigenvalue really represents.
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Oftentimes, students end up well-practiced in the numerical operations of matrices, but are only vaguely aware of the geometric intuitions underlying it all.
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But there's a fundamental difference between understanding linear algebra on a numeric level and understanding it on a geometric level.
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Each has its place, but roughly speaking, the geometric understanding is what lets you judge what tools to use to solve specific problems,
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feel why they work, and know how to interpret the results.
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And the numeric understanding is what lets you actually carry through the application of those tools.
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Now, if you learn linear algebra without getting a solid foundation in that geometric understanding, the problems can go unnoticed for a while,
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until you've gone deeper into whatever field you happen to pursue, whether that's computer science, engineering, statistics, economics, or even math itself.
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Once you're in a class, or a job for that matter, that assumes fluency with linear algebra,
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the way that your professors or your co-workers apply that field could seem like utter magic.
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They'll very quickly know what the right tool to use is, and what the answer roughly looks like in a way
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that would seem like computational wizardry if you assume that they're actually crunching all the numbers in their head.
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Here, as an analogy, imagine that when you first learned about the sine function in trigonometry, you were shown this infinite polynomial.
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This, by the way, is how your calculator evaluates the sine function.
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For homework, you might be asked to practice computing approximations of the sine function, by plugging in various numbers to the formula and cutting it off at a reasonable point.
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And in fairness, let's say you had a vague idea that this was supposed to be related to triangles, But exactly how had never really been clear, and was just not the focus of the course.
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Later on, if you took a physics course, where sines and cosines are thrown around left and right, and people are able to tell pretty immediately how to apply them
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and roughly what the sign of a certain value will be, it would be pretty intimidating, wouldn't it?
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It would make it seem like the only people who are cut out for physics are those with computers for brains, and you would feel unduly slow or dumb for taking so long on each problem.
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It's not that different with linear algebra.
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And luckily, just as with trigonometry, there are a handful of intuitions, visual intuitions, underlying much of the subject.
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And unlike the trig example, the connection between the computation and these visual intuitions is typically pretty straightforward.
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And when you digest these, and really understand the relationship between the geometry and the numbers, the details of the subject, as well as how it's used in practice,
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start to feel a lot more reasonable.
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In fairness, most professors do make an effort to convey that geometric understanding.
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The science example is a little extreme.
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But I do think
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that a lot of courses have students spending a disproportionate amount of time on the numerical side of things, especially given that in this day and age,
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we almost always get computers to handle that half, while in practice, humans worry about the conceptual half.
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So this brings me to the upcoming videos.
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The goal is to create a short, binge-watchable series animating those intuitions from the basics of vectors up through the core topics
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that make up the essence of linear algebra.
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I'll put out one video per day for the next five days, then after that put out a new chapter every one to two weeks.
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I think it should go without saying that you cannot learn a full subject with a short series of videos, and that's just not the goal here.
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But what you can do, especially with this subject, is lay down all the right intuitions
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so the learning that you do moving forward is as productive and fruitful as it can be.
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I also hope this can be a resource for educators who are teaching courses that assume fluency with linear algebra, giving them a place to direct students that need a quick brush up.
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I'll do what I can to keep things well paced throughout, but it's hard to simultaneously account for different people's different backgrounds and levels of comfort,
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so I do encourage you to readily pause and ponder if you feel that it's necessary.
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Actually, I'd give that same advice for watching any math video, even if it doesn't feel too quick, since the thinking that you do on your own time is where all the learning really happens, don't you think?
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So, with that as an introduction, I'll see you next video.

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本課的詞彙與口語要點

這節 C1 級別的口語課以影片“Essence of linear algebra preview”為素材。 影片中反覆出現的詞有:algebra, linear, understanding, intuitions, geometric。 這段影片共有 47 個句子、917 個單詞可供跟讀。 講話部分時長為 4:43。 說話人語速較快,每分鐘約 195 個詞,會出現較多連讀和弱讀。 只有 81% 的單詞屬於英語最常用的 3,000 詞,詞彙難度較高。

影片中的重點詞彙

影片中最難的 15 個單詞,附發音和釋義:

單詞發音釋義
algebra 名詞/ˈæl.d͡ʒɪ.bɹə/代數 /代數
intuition 名詞/ˌɪn.tjuːˈɪʃ.ən/直覺 /直覺, 直感
sine 名詞/saɪn/正弦
determinant 名詞/dɪˈtɜːmɪnənt/決定(性)因素 /決定(性)因素
compute 動詞/kəmˈpjuːt/計算 /計算
eigenvalue 名詞/ˈaɪ.ɡənˌvæl.ju/特徵值 /特徵值, 本徵值 /本徵值
fluency 名詞/ˈfluːənsi/流暢 /流暢
multiplication 名詞/ˌmʌltɪplɪˈkeɪʃən/乘法
trigonometry 名詞/ˌtɹɪɡəˈnɒmətɹi/三角法, 三角學 /三角學
numerical 形容詞/n(j)uːˈmɛɹ.ɪ.kəl/數值的 /數值的
animate 形容詞/ˈæn.ə.mət/活的, 有生命的
cosine 名詞/ˈkoʊ.saɪn/餘弦 /餘弦
intimidate 動詞/ɪnˈtɪmɪdeɪt/威脅 /威脅, 恐嚇 /恐嚇
polynomial 名詞/ˌpɑliˈnoʊmiəl/多項式 /多項式
ponder 動詞/ˈpɑn.dəɹ/思考, 琢磨

影片中出現的短語動詞

單詞發音釋義
come out 動詞/ˌkʌm ˈaʊt/出, 出來 /出來
end up 動詞到達
go through 動詞通過 /通過
lie down 動詞偃, 躺下
make up 動詞/ˌmeɪk ˈʌp/組成 /組成

影片中的語法

說話人最常用的結構,並附上影片中的原話:

結構影片中的用法
被動語態 be + 過去分詞 — 強調發生了什麼,而不是誰做的is defined · were shown · might be asked
現在完成時 have/has + 過去分詞 — 過去發生但與現在仍有關聯的事I've noticed · you've gone

需要注意的發音

說話人用了 15 次縮略和弱讀形式,例如 I'll, I'm, they'll。請按聽到的簡短形式來說。

  • “sh” 和 “zh” 音: intuition /ˌɪn.tjuːˈɪʃ.ən/, multiplication /ˌmʌltɪplɪˈkeɪʃən/, approximation /əˌpɹɑk.sɪˈmeɪ.ʃən/, computation /ˌkɑmpjʊˈteɪʃn̩/, disproportionate /dɪs.pɹəˈpɔː.ʃə.nət/
  • 長單詞——注意重音位置: intuition /ˌɪn.tjuːˈɪʃ.ən/, geometric /ˌd͡ʒiː.əʊˈmɛt.ɹɪk/, determinant /dɪˈtɜːmɪnənt/, eigenvalue /ˈaɪ.ɡənˌvæl.ju/, multiplication /ˌmʌltɪplɪˈkeɪʃən/

中文母語者容易讀錯的音:

  • /v/ — 不要讀成 /w/,上齒輕觸下唇: eigenvalue /ˈaɪ.ɡənˌvæl.ju/, vaguely /ˈveɪɡli/, convey /kənˈveɪ/, vague /veɪɡ/, vector /ˈvɛktɚ/
  • 詞尾子音 — 要讀清楚,後面不要加母音: geometric /ˌd͡ʒiː.əʊˈmɛt.ɹɪk/, determinant /dɪˈtɜːmɪnənt/, matrix /ˈmeɪ.tɹɪks/, compute /kəmˈpjuːt/, numeric /n(j)uːˈmɛɹɪk/
  • /r/ 和 /l/ 的區別: algebra /ˈæl.d͡ʒɪ.bɹə/, numerical /n(j)uːˈmɛɹ.ɪ.kəl/, fruitful /ˈfɹuːtfl̩/, triangle /ˈtɹaɪˌæŋɡəl/, readily /ˈɹɛdɪli/

如何用這段影片練習

  1. 先完整聽一遍影片,不要開口,記下不認識的單詞。
  2. 先用 0.75 倍速逐句跟讀,熟練之後再回到正常速度。
  3. 錄下自己的聲音並與原聲對比,特別注意 algebra, intuition, sine 這類單詞。

什麼是跟讀法?

跟讀法 (Shadowing) 是一種有科學依據的語言學習技巧,最初開發用於專業口譯員的培訓,並由多語言者Alexander Arguelles博士普及。這個方法簡單而強大:您在聽英語母語原聲的同時立即大聲重複——就像是一個延遲1-2秒緊跟說話者的影子。與被動聽力或語法練習不同,跟讀法強迫您的大腦和口腔肌肉同時處理並模模擬實的講話模式。研究表明它能顯著提高發音準確性,語調,節奏,連讀,聽力理解和口語流利度——使其成為雅思口語備考和真實英語交流最有效的方法之一。

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