Typo on Stage 3 ,Probabilities, 5.1

本文由 Au Yeung Yat 在 2015-08-13 發表於 "數學" 討論區

  1. 57589507

    Au Yeung Yat
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    "The consideration above is exactly the same as the argument leading to the definition of expection in previous chapter. In fact,
    E(X) = 10, 000, 000P(X = +10, 000, 000)− 5P(X = −5) ≈ −4.285

    That is, if we play the game many times, we should expect to lost roughly $4,285 per game. "
    4.285=4,285 ?!
     
    #1 Au Yeung Yat, 2015-08-13
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    56377379
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    回覆 1# Au Yeung Yat


    Apparently this is a typo. We will contact the maintainer of the question pool to follow up the case.

    -- by Guo Xin
     
    #2 56377379, 2015-08-14
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    56377379
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    I have just got the reply that the figure has been updated accordingly.

    -- by Guo Xin
     
    #3 56377379, 2015-08-17
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    Au Yeung Yat
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    Also,(Level 3 Complex Number, Ch.3 Theorem 3.3)
    "Please be reminded again that, we are using radians(rad) as the measure unit for all angels and arguments."
     
    #4 Au Yeung Yat, 2015-08-18
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    回覆 4# Au Yeung Yat

    Er... the sentence appears OK, right? What is your question?

    -- by Guo Xin
     
    #5 56377379, 2015-08-19
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    Au Yeung Yat
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    回覆 5# Mathematics tutor 1

    "...we are using radians(rad) as the measure unit for all angels and arguments."
     
    #6 Au Yeung Yat, 2015-08-19
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    回覆 6# Au Yeung Yat


    Although I still am confused about your question, I guess what you asked is "how can radian be the measure of an angle?", is that correct?

    Radian is used to measure the angle. There is no unit, and if used, the trigonometric functions enjoy good Taylor expansions. Approximately 1 rad equals 57.29578 degrees. For details, see the wikipedia page https://en.wikipedia.org/wiki/Radian, or some standard middle school mathematics textbooks.

    Please do not hesitate to let me know if this still does not answer your question.

    -- by Guo Xin
     
    #7 56377379, 2015-08-20
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    Au Yeung Yat
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    本帖最後由 Au Yeung Yat 於 2015-8-29 00:18 編輯

    回覆 7# Mathematics tutor 1
    1 angle is NOT 1 angel
     
    #8 Au Yeung Yat, 2015-08-29
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    回覆 8# Au Yeung Yat


    Thank you for the kind comment and your point is absolutely right. Let me forward the comment to the forum maintainer to follow up.

    -- by Guo Xin
     
    #9 56377379, 2015-08-29
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    回覆 8# Au Yeung Yat


    Typo reported and I got the reply from the Gifted Education Section that the typo will be fixed in the coming revision of content.

    Many thanks for reporting.

    -- by Guo Xin
     
    #10 56377379, 2015-08-29