如何停车也可以用公式算出?

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生活在大城市的人们基本上都碰到过停车难的情况，下面通过公式带给我们的启发知道只要满足公式的条件要求，我们都可以停车，不会再因为停车空间而烦恼！

If you live in a big city, this scenario is all too familiar: Traffic is bad. You're late for work. And, of course, the parking garage is now full. So you're forced to parallel park on the street. You finally find a spot between two hulking SUVs, but it looks pretty tight. Do you go for it or move on?

生活在大城市的你都遇到过这样的情况吧：塞车！迟到！停车位已满！因此你不得不决定把爱车停在大街上。好不容易找到2辆SUV的些许间隙，可是它看起来是如此紧密。停？还是不停？这是个问题。

Not to worry; geometry can save you. Run a simple calculation and - voila! - you'll know just what to do.

不用担心，几何学来帮你。只要一个公式，一切烦恼冲云霄。

Ignore the car that's sneaking into your space as you do the calculation. You'll need a few pieces of information:

先不用管身旁大吼的宝贝车，开始数学课吧。

Your car's turning radius, r
The distance between the front and rear wheels, l
The distance from your front wheel to the corner of the front bumper, k
The width of the car you're trying to park behind, w

需要的信息：你车的转向半径r，前轮和后轮的距离，轮到前保险杠的距离k，你车停在后面的宽度w。

Now it's simply a matter of plugging those variables into the handy formula (see our illustration), and you'll know if that spot could have been yours.

现在就是把这些变量塞到公式里啦，然后就马上可以回答那个生命有关的问题。

The formula for the perfect parking job was recently worked out by mathematician Simon Blackburn, professor at the University of London. Stanford mathematics professor Keith Devlin tells NPR's Audie Cornish "it's actually a very clever use of simple mathematics."

这个完美停车公式是最近由伦敦大学的数学家Simon Blackburn教授提出的。史丹佛大学数学教授Keith Devlin告诉NPR记者Audie Cornish：“这其实是一个从最简单的数学提炼出的非常高明的方式。”

The most complicated part, Devlin says, is our good old friend the Pythagorean theorem. That's a squared plus b squared equals c squared, as you'll remember from your high school geometry class, no doubt.

Devlin说，最复杂的部分便是我们熟知的毕达哥拉斯定理。这个理论在高中几何学课堂上就学过啦。

"The formula tells you exactly how much extra space you need, beyond the length of your vehicle, in order to park it in a simple, reverse-in, straighten-the-wheels, switch-the-engine-off move," Devlin explains. In other words, no back-and-forth, no see-sawing - the perfect parallel parking job.

Devlin解释说：“这个公式精确的告诉你需要停车的适当距离，无论你的车长多少，只要扭转、直轮、刹车，没有前后摇动、没有左右摆不停，让你完美停车，完美动作。”

Blackburn's formula does this by sketching the arc of your car's turning capability into a full circle, then using the center of the circle to create the right-angle triangles Pythagoras loved.

Blackburn教授的公式通过对车的弧度和转角能力画圈，利用圆心来设置一个直角三角形。

That's a lot of work just to tell you if you have enough space for an easy park. And it doesn't tell you how to do the parking. That's something you have to learn by doing, which is how most people figure out whether they have enough space to park in the first place. Devlin says that behind all that guessing, math is at work.

这样就足以告诉你是否有足够的空间顺利停车。不过这并没有告诉你怎样停车。你必须通过实践来熟悉和清楚，那就是为什么有的人第一眼就知道这个停车位是否有足够的空间。

"Mathematics gives you a way of understanding in detail what people have learned to do simply by practice and expertise," he says.

他说：“人们只是简单地通过操作来知道怎么做，而数学就帮我们理解为什么这么做可以做到的原因。”

"In fact, when we practice something, be it on the athletic field or in an automobile, we are becoming very good mathematicians at doing a particular kind of operation," Devlin says. "But usually we don't call it mathematics - and we certainly don't give people a pass on the math test because they can park their car."

Devlin教授说：“实际上，无论是在体育还是机动领域，人们在解决某些事情的时候已经成为数学家。不过一般我们不把它和数学练习起来——我们不会因为你知道怎么停车而给你的数学考试打及格。”