Class 12

Math

Algebra

Vector Algebra

Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are $2(a+b)$and $(a−3b)$externally in the ratio 1 : 2. Also, show that P is the mid point of the line segment RQ

$RP+PQRP =21 $

RP=PQ

So, P is mid point of RQ

$P−R=Q −P$$r=2p −q $$r=2(2a+b)−(a−3b)$$r=3a+5b$