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c***g
发帖数: 472 | 1 A dart is thrown at a circular dart board of radius one. The dart can land
at any place on the dartboard with equal probability. What is the mean
distance between where the dart hits and the center of the board?
solution 是这样的:
Lets consider the dartboard in polar coordinates. The dart can land at any
angle relative to the center with equal probability. Next take the intregral
from the least to the greatest distance, 0 to 1. The density function at
distance d is 2*pi*d/pi = 2d.
请问这里的density funct | i*****e
发帖数: 5233 | 2 1/pi 其实是 1/(pi*R^2) R=1
intregral
【在 c***g 的大作中提到】
: A dart is thrown at a circular dart board of radius one. The dart can land
: at any place on the dartboard with equal probability. What is the mean
: distance between where the dart hits and the center of the board?
: solution 是这样的:
: Lets consider the dartboard in polar coordinates. The dart can land at any
: angle relative to the center with equal probability. Next take the intregral
: from the least to the greatest distance, 0 to 1. The density function at
: distance d is 2*pi*d/pi = 2d.
: 请问这里的density funct
| g**********1
发帖数: 1113 | 3 圆盘上的对r=sqrt(x^2+y^2)的面积分，做个坐标变换就行了。 | h**6
发帖数: 4160 | |
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