Question

Which relationships hold true for the sum of the magnitudes of vectors u and v, which are perpendicular?

Answer 1

it is

B) ||u+v|| = sqrt ||u||2 + ||v||2

AND

D) ||u+v|| less than ||u||+||v||

Answer 2

check the picture below.

notice, the sum of u+v yields the red vector, and its magnitude is smaller than the sum of the other two green ones.