find distance from pt (2, -5) to line r = (1, 3) + t(-2, 8)

[JAsh]

determine the distance from the point A(2, -5) to the line r= (1,3) + t (-2,8)

i could do it if instead of a line they gave another point, but i dont know how to do it like this

help?

 

[Deleted member 4993]

Re: using vectors to find distance

determine the distance from the point A(2, -5) to the line r= (1,3) + t (-2,8)

i could do it if instead of a line they gave another point, but i dont know how to do it like this

help?

The parametric representation of line will give the co-ordinate of point on the line - when you assign a value of 't'.

so

for t = 0 you get (1,3)

for t =1 you get (-1, 11)

for t = 3 you get (-5, 27)


all these are points on the line.

So now draw a vector between these two points, define a unit vector along the line - take cross-product - and you have the distance.

I am sure your textbook has some example problems just like this. If not try googling "distance line point".

If you still have problem - write back showing your work, so that we know where to begin to help you.