The unit vector in the direction of sum of vectors $3 \vec{i}+5 \vec{j}-4 \vec{k}$ and $\vec{i}-2 \v

Question

The unit vector in the direction of sum of vectors $3 \vec{i}+5 \vec{j}-4 \vec{k}$ and $\vec{i}-2 \vec{j}+3 \vec{k}$ is

Professor PC Thomas Classes · Answer

Sum vector is $(3+1)\vec{i} + (5-2)\vec{j} + (-4+3)\vec{k} = 4\vec{i} + 3\vec{j} - \vec{k}$. Divided by its magnitude $\sqrt{26}$ constructs the unit vector.