Can you solve the Alice in Wonderland riddle? - Alex Gendler

2,176,362 views ・ 2020-11-17

TED-Ed


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翻译人员: Chuqi Hu 校对人员: Yolanda Zhang
00:07
After many adventures in Wonderland,
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在仙境经历了许多冒险后,
00:10
Alice has once again found herself in the court
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爱丽丝发现自己再一次来到了
00:12
of the temperamental Queen of Hearts.
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喜怒无常的红皇后的庭院。
00:15
She’s about to pass through the garden undetected,
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正当她要悄悄溜过花园时,
00:18
when she overhears the king and queen arguing.
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她听到了国王和皇后在争论
00:21
“It’s quite simple,” says the queen. “64 is the same as 65, and that’s that.”
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“显而易见,” 皇后说, “64 和 65 是一样的,就这样。”
00:27
Without thinking, Alice interjects. “Nonsense,” she says.
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爱丽丝不假思索就插话了。 “胡说,”她说,
00:31
“If 64 were the same as 65, then it would be 65 and not 64 at all.”
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“64 要是和 65 一样, 它就是 65,根本不是 64 了。”
00:38
“What? How dare you!” the queen huffs.
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皇后发怒道, “什么?你好大的胆子!”
00:41
“I’ll prove it right now, and then it’s off with your head!”
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“我现在就来证明, 你就等着掉脑袋吧!”
00:44
Before she can protest,
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还没来得及反抗,
00:46
Alice is dragged toward a field with two chessboard patterns—
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爱丽丝就被拽到了一块空地, 那里有两个棋盘图案——
00:50
an 8 by 8 square and a 5 by 13 rectangle.
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一个是 8x8 的正方形, 另一个是 5x13 的长方形。
00:55
As the queen claps her hands, four odd-looking soldiers approach
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皇后拍了拍手后, 来了四个外形古怪的士兵
01:00
and lie down next to each other, covering the first chessboard.
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他们相邻躺下, 把第一个棋盘盖住了。
01:03
Alice sees that two of them are trapezoids with non-diagonal sides measuring 5x5x3,
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爱丽丝看见其中两个士兵是梯形的, 斜边以外的边长是 5x5x3,
01:11
while the other two are long triangles with non-diagonal sides measuring 8x3.
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另外两个士兵是三角形, 斜边之外的两个边长是 8x3。
01:18
“See, this is 64.”
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“看,这就是64。”
01:20
The queen claps her hands again.
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皇后又拍了拍手,
01:22
The card soldiers get up, rearrange themselves,
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纸牌士兵们站了起来, 重新排列,
01:25
and lie down atop the second chessboard.
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然后躺下,盖住了第二个棋盘。
01:29
“And that is 65."
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“而这就是65。”
01:31
Alice gasps. She’s certain the soldiers didn’t change size or shape
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爱丽丝一惊。她敢肯定士兵们 从一个棋盘移到另一个棋盘时
01:36
moving from one board to the other.
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没有改变大小和形状。
01:38
But it’s a mathematical certainty that the queen must be cheating somehow.
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但从数学角度出发, 皇后肯定以某种方式作弊了。
01:42
Can Alice wrap her head around what’s wrong— before she loses it?
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在丢掉脑袋之前, 爱丽丝能想出问题出在哪里吗——
01:46
Pause the video to figure it out yourself. Answer in 3.
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【请暂停视频来思考答案】 【答案即将公布:3】
01:49
Answer in 2
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【2】
01:51
Answer in 1
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【1】
01:54
Just as things aren’t looking too good for Alice, she remembers her geometry,
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就在情况看起来对爱丽丝很不利时, 她想到了几何。
01:59
and looks again at the trapezoid and triangle soldier
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她又看了看相邻躺下的
02:03
lying next to each other.
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梯形和三角形士兵。
02:04
They look like they cover exactly half of the rectangle,
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他们貌似正好盖住了半个长方形,
02:08
their edges forming one long line running from corner to corner.
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他们的边缘形成了一条 从一个端点到对角端点的长线。
02:12
If that’s true, then the slopes of their diagonal sides
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如果这是真的, 他们斜边的斜率
02:16
should be the same.
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就应该是一样的。
02:17
But when she calculates these slopes
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但是当她用斜率公式
02:19
using the tried and true formula "rise over run,"
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“竖直位移比水平位移” 计算斜率时,
02:23
a most curious thing happens.
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神奇的事情发生了。
02:26
The trapezoid soldier’s diagonal side goes up 2 and over 5,
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梯形士兵的斜边是 竖直 2,水平 5,
02:30
giving it a slope of two fifths, or 0.4.
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也就是说斜率是 2/5, 或者说 0.4。
02:34
The triangle soldier’s diagonal, however, goes up 3 and over 8,
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但三角形士兵的斜边是 竖直 3,水平 8,
02:40
making its slope three eights, or 0.375.
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斜率是 3/8, 或者说 0.375。
02:45
They’re not the same at all!
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它们根本就不一样!
02:47
Before the queen’s guards can stop her,
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在皇后的守卫阻止她之前,
02:49
Alice drinks a bit of her shrinking potion to go in for a closer look.
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爱丽丝喝了点缩小药水, 走近瞧了瞧。
02:54
Sure enough, there’s a miniscule gap between the triangles and trapezoids,
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的确,在三角形和梯形之间 存在一个微小的间隙。
02:58
forming a parallelogram that stretches the entire length of the board
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形成了一个从棋盘的一角 延伸到对角的平行四边形。
03:03
and accounts for the missing square.
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这也解释了少掉的方格去了哪里。
03:06
There’s something even more curious about these numbers:
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这些数字还有更奇妙的特征:
03:10
they’re all part of the Fibonacci series,
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它们都是斐波那契数列的一部分,
03:12
where each number is the sum of the two preceding ones.
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也就是说,每个数字 都是之前两个数字的和。
03:17
Fibonacci numbers have two properties that factor in here:
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斐波那契数列有两个特性 在这里起到了作用:
03:21
first, squaring a Fibonacci number gives you a value
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首先,一个斐波那契数的平方
03:25
that’s one more or one less
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比相邻它的两个数的乘积
03:27
than the product of the Fibonacci numbers on either side of it.
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多 1 或者少 1。
03:31
In other words, 8 squared is one less than 5 times 13,
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换句话说,8 的平方 比 5 乘 13 少 1。
03:35
while 5 squared is one more than 3 times 8.
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而 5 的平方比 3 乘 8 多 1。
03:40
And second, the ratio between successive Fibonacci numbers is quite similar.
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其次,连续的两个 斐波那契数的比率很相近。
03:46
So similar, in fact, that it eventually converges on the golden ratio.
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实际上是非常相近,以至于 最后收敛到了黄金比例的数值。
03:51
That’s what allows devious royals to construct slopes
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这也是为什么阴险的皇室
03:55
that look deceptively similar.
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能构建出看似一致的斜率。
03:57
In fact, the Queen of Hearts could cobble together an analogous conundrum
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实际上,红皇后用任意四个 连续的斐波那契数,
04:02
out of any four consecutive Fibonacci numbers.
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都可以设计出类似的谜题。
04:06
The higher they go, the more it seems like the impossible is true.
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数字越大,不可能的情况 越看起来是真的。
04:10
But in the words of Lewis Carroll— author of Alice in Wonderland
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但正如爱丽丝梦游仙境的作者, 以及研究了这个谜题的杰出数学家
04:14
and an accomplished mathematician who studied this very puzzle—
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刘易斯·卡罗尔 ( Lewis Carroll)所说,
04:19
one can’t believe impossible things.
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“一个人不能相信不可能的事情。”
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