With respect to a rectangular Cartesian coordinate system, three vectors are expressed as
`vec(a)= 4hat(i)-hat(j), vec(b)= -3hat(i)+2hat(j) and vec(c )= -hat(k)`
Where, `hat(i), hat(j), hat(k)` are unit Vector, along the X, Y and Z-axis respectively. The unit vectors `hat(r )` along the direction of sum of these vector is