# Math Help - distance between two lines

1. ## distance between two lines

i need help finding the shortest distance between lines pq and rs
p=(2,1,3) q=(1,2,1) r=(-1,-1,-2) S=(1,-4,0)

i realize i already posted a thread on this but it appears to have been deleted and i cant find it.

2. Given two skew lines $P+tD~\&~Q+tE$ then the distance between them is:
$\frac{{\left| {\overrightarrow {PQ} \cdot \left( {D \times E} \right)} \right|}}{{\left\| {\left( {D \times E} \right)} \right\|}}$

3. Originally Posted by leinadwerdna
i need help finding the shortest distance between lines pq and rs
p=(2,1,3) q=(1,2,1) r=(-1,-1,-2) S=(1,-4,0)

i realize i already posted a thread on this but it appears to have been deleted and i cant find it.
http://www.mathhelpforum.com/math-he...questions.html

4. Originally Posted by Plato
Given two skew lines $P+tD~\&~Q+tE$ then the distance between them is:
$\frac{{\left| {\overrightarrow {PQ} \cdot \left( {D \times E} \right)} \right|}}{{\left\| {\left( {D \times E} \right)} \right\|}}$
how do u get the lines into the form P+tD and Q+te

5. Originally Posted by leinadwerdna
how do u get the lines into the form P+tD and Q+te
From the series of your questions, it seems that you are asking for a basic course in vector geometry. We are not prepared to offer instruction. You ought to have text material that contains this basic material.