# Math Help - Vector

1. ## Vector

If
u, v is a member ofR^n, find u · v given that |u + v| = 1 and |u v| = 5.

2. Originally Posted by ah-bee
If
u, v is a member ofR^n, find u · v given that |u + v| = 1 and |u v| = 5.
HINT: $|u+v|^2 - |u-v|^2 = 4(u.v)$