Find the position vector of a point `R` which divides the line joining the two points `P` and `Q` with position vectors `vec(OP)=2veca+vecb` and `vec(OQ)=veca-2vecb`, respectively in the ratio `1:2` internally and externally.

Explanation

Given,

it divide internally in ratio `1:2`

So,`R=(OP+10Q)/3
​`

`​R=(3a+2b+a−2b)/3
​=(4a)/3`

​
And,

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