Find a constant vector parallel to the line given parametrically by:
$$x = 1 - a$$ $$y = 2 + 3a$$ $$z = 1 + a$$
I made $a$ the subject and worked out the equation of a line represented by this as $r = (-i + 2j + k) + a(i + 3j + k)$. This means a constant vector parallel to the line would be $i + 3j + k$.
Is this correct ?