# Vector..

• May 1st 2013, 04:37 AM
Trefoil2727
Vector..
It is given that OA=a and OB=b. Find OR in each of the following cases:
a) R is a point on the straight line AB such that AR : RB=1:2
b) R lies on the extended straight line AB such that AR:RB= 4:3
c) R is the midpoint of the straight line AB
I solved (a), but I don't know what is the mean of 'extended straight line'
• May 1st 2013, 05:15 AM
Prove It
Re: Vector..
It means you go out further than the end of the original vector...
• May 1st 2013, 06:41 AM
HallsofIvy
Re: Vector..
Quote:

Originally Posted by Trefoil2727
It is given that OA=a and OB=b. Find OR in each of the following cases:
a) R is a point on the straight line AB such that AR : RB=1:2

So the distancde from B to R is twice the distance from A to R. And that means that the distance from A to R is 1/3 the distance from A to B.

Quote:

b) R lies on the extended straight line AB such that AR:RB= 4:3
So the distance from A to R is 4/3 the distance from B to R. And that means that the distance from A to B is 4/(4+3)= 4/7b thwe distance from A to R.

Quote:

c) R is the midpoint of the straight line AB
I solved (a), but I don't know what is the mean of 'extended straight line'
• May 2nd 2013, 07:01 AM
Trefoil2727
Re: Vector..
still don't understand..how to find OR?