What we actually care about is the square of a distance, so it will just be y squared.
我们关心的是，距离的平方，所以它就是y的平方。
2
a perfectly spherical shell dr at some distance, thickness, d r, dr we talk about it as 4 pi r squared d r, so we just multiply that by the probability density.
在某个地方的完美球型壳层,厚度，我们把它叫做4πr平方，我们仅仅是把它,乘以概率密度。
3
The slope of the best fit line for distance doubled and time squared gives the acceleration due to gravity.