Distance from a point to a line using vectors – video clip


The distance from a point described by the vector s to the line

r = a + tb

is |(sab| if we make b a unit vector

or, more generally, |(sab|/|b|

This video works through an example carefully and clearly. Just one word of warning: the video uses a for the direction vector of the line (what we usually call b):

and b for what we’ve called sa.