Find the position vector of a point R which divides the line segment joining points P ( ^ i + 2 ^ j + ^ k ) and Q ( ^ i + ^ j + ^ k ) internally.

Question

Find the position vector of a pointR which divides the line segment joining points [P \left( \hat{i} + 2 \hat{j} + \hat{k} \right) \text{ and Q }\left( - \hat{i} + \hat{j} + \hat{k} \right)] internally 2:1.