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數學和數學家的故事
hangchoi:
The first time we touched this book is Book 2, which one of us borrowed it from library........
kido:
--- Quote from: hangchoi on 21 October 2009, 00:47:40 ---The first time we touched this book is Book 2, which one of us borrowed it from library........
--- End quote ---
Book 2 was the first book I read.... Cannot remember exactly what it contains, but definitely good. (That makes me to continue to read Book 1, then Book 4.... Book 3 is sort of boring) I cannot find my book 4 now, but I remember the prove of the equality of Isosceles triangle's base angles, by means of computer, was shocking:
If you look at 10 out of 10 maths text books, it involves making an artificial bi-sector line. However, without making a bi-sector line, how do you prove their base angles are equal?
[Will post it here on the other day....]
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[update 2nd Nov]
I still couldn't find the book. Also surprise that there is no such clever prove on the net. This is the usual method. I remembered the shocking prove was like that:
AB = AC (given)
∠BAC = ∠CAB (given)
BC = CB (common size)
∴△ABC≡△ACB (SAS)
∴∠ABC=∠ACB
hangchoi:
Book 2 is very good.....It talks about inter alias, the remainder theorem. A trick of which is teached in a poem, which I can still recall :
三人同行七十里
五馬二十一人騎
七子回家半個月
除百零五是佳期
You think of a number, and you give me the remainder of that number by dividing it by 3, 5, and 7. I can apply these remainder to calculate what the number is by using the above poem. Remember that?
chin:
--- Quote from: hangchoi on 27 October 2009, 10:53:31 ---Book 2 is very good.....It talks about inter alias, the remainder theorem. A trick of which is teached in a poem, which I can still recall :
三人同行七十里
五馬二十一人騎
七子回家半個月
除百零五是佳期
You think of a number, and you give me the remainder of that number by dividing it by 3, 5, and 7. I can apply these remainder to calculate what the number is by using the above poem. Remember that?
--- End quote ---
Yes I remember this. Thank you for reminding me of this poem.
Maybe I should find these books for my kids...
kido:
--- Quote from: hangchoi on 27 October 2009, 10:53:31 ---三人同行七十里
五馬二十一人騎
七子回家半個月
除百零五是佳期
--- End quote ---
How come I have no impression at all? This trick is same as 韓信大點兵 ?
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