If $$ \overrightarrow {a} = \hat{i} + \hat{j} + \hat{k} $$ and
$$ \overrightarrow {b} = 2\hat{i} − \hat{j} + 3\hat{k}$$ and
$$ \overrightarrow {c} = \hat{i} − 2\hat{j} + \hat{k} $$
find a unit vector parallel to the vector $$2\overrightarrow {a} – \overrightarrow {b} + 3 \overrightarrow {c} $$
