Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are 
respectively, in the ratio 2 : 1
(i) internally (ii) externally
Given that 
and 
(i) The 
lies on the segment PQ(internal division).If m:n is the ratio in which 
divides PQ, then
Given m:n=2:1, m=2 and n=1
(ii) The 
does not lie on the segment PQ(external division).If m:n is the ratio in which 
divides PQ,then
Given m:n=2:1, m=2 and n=1
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