These are the questions I didn't get from my vectors homework tonight.

Note that vectors are represented by bolded letters.

1. What conditions must be satisfied by the vectors u and v for |u+v|>|u-v| to be true?

2. Illustrate for k>0 that k(u+v) = ku + kv.

3. By considering the angles between the vectors show that a+b and a-b are perpendicular when |a| = |b|.