Average distance point to line 3d maybe

Average distance point to line 3d maybe

Postby Guest » Fri Aug 16, 2024 8:15 pm

We have a 3d line with both end points known and another point with its coordinates known in 3d, how to find average distance to all points of said line from said other point? Can you connect with me, maybejosiah@aol.com if you have an answer?
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Re: Average distance point to line 3d mayb

Postby Guest » Thu Jan 30, 2025 11:03 am

let the coordinates of all three points be [tex](x_i,y_i,z_i)[/tex] where [tex]i=1,2,3[/tex] such that the third point is external to the line. Now, the parametric representation of any general point on the line is [tex]P(u)=\begin{cases} x=x_1+u(x_2-x_1) \\ y = y_1+u(y_2-y_1) \\ z=z_1+u(z_2-z_1) \end{cases}[/tex], where [tex]u\in[0,1][/tex]. Now, the distance from the third point to this general point is [tex]\sqrt{\left\{x_3-x_1-u(x_2-x_1)\right\}^2+\left\{y_3-y_1-u(y_2-y_1)\right\}^2+\left\{z_3-z_1-u(z_2-z_1)\right\}^2}[/tex].

So, taking the average over the entire interval, we get
[tex]\frac{1}{1-0}\int\limits_{0}^{1}\sqrt{\left\{x_3-x_1-u(x_2-x_1)\right\}^2+\left\{y_3-y_1-u(y_2-y_1)\right\}^2+\left\{z_3-z_1-u(z_2-z_1)\right\}^2}\,du[/tex]
[tex]=\boxed{\int\limits_{0}^{1}\sqrt{\left\{x_3-x_1-u(x_2-x_1)\right\}^2+\left\{y_3-y_1-u(y_2-y_1)\right\}^2+\left\{z_3-z_1-u(z_2-z_1)\right\}^2}\,du}[/tex]
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Re: Average distance point to line 3d maybe

Postby Guest » Thu Jan 30, 2025 12:42 pm

Alright thanks maybe or maybe not, maybe.
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