Question

is the following equation correct?
| vector a + vector b | = | vector a | + | vector b |
if yes, when? If no, why not?

Answer 1

no equation is not correct because magnitude of vector a + vector b = square root of square of magnitude of A vector + square of magnitude of B vector + 2 into magnitude of A vector into magnitude of B vector  into cos of angle between the 2 vectors
This equation can be only correct if angle between vector A and vector B is 0 degree