Answer
$(1,-1,-1)$
Work Step by Step
Formula to calculate the unit vector $\hat{\textbf{u}}$ is: $\hat{\textbf{u}}=\dfrac{u}{|u|}$
$u=\overrightarrow{P_1P_2}=P_2-P_1$
Here,$P_1$ and $P_2$ are two vectors and $u=2i-2j-2k$; $|u|=\sqrt{(2)^2+(-2)^2+(-2)^2}=\sqrt{4+4+4}= 2\sqrt {3}$
Thus, $\hat{\textbf{u}}=\dfrac{2i-2j-2k}{2 \sqrt 3}=(\dfrac{1}{\sqrt 3} i-\dfrac{1}{\sqrt 3}j-\dfrac{1}{\sqrt 3}k)$
Apply Mid-point formula.
Thus, we have $(\dfrac{x_1+x_2}{2},\dfrac{y_1+y_2}{2},\dfrac{z_1+z_2}{2})=(\dfrac{0+2}{2},\dfrac{0+(-2)}{2},\dfrac{0+(-2)}{2})$
or, $=(1,-1,-1)$
