When one of the vectors is a zero vector:

length(u + 0) <= length(u) + length(0)

Adding the Zero Vector

Add the zero matrix ( 0, 0 )^T to the matrix ( 4, 3 )^T. If (0, 0)^T represents a displacement vector, it means do nothing to change position.

Now consider what this might mean: add the vector (1, 2)^T to the point (4, 4)^T.

If you think that makes sense, then do the calculation. What type of object is the result?