Mathematics for IGCSE & O level - Vectors (Section 4 - No. 44)
If a and b are two non-zero vectors and |a + b| = |a| + |b|, what does this imply about the relationship between vectors a and b?
a and b are perpendicular
a and b are parallel and in the same direction
a and b are parallel but in opposite directions
There is no direct relationship between a and b
Explication
If the sum of the magnitudes equals the magnitude of the sum, the vectors are in the same direction.