# Finding angle between two unit vectors

• Dec 2nd 2009, 09:18 PM
Finding angle between two unit vectors
Hello

Given two unit vectors A,B and their sum (vector C) which is also a unit vector, find the angle between B and C?

• Dec 2nd 2009, 09:29 PM
qmech
When working with vectors, you usually compute the angle by
$
cos \theta = \frac {\vec A \cdot \vec B}
{ A B }
$

where the denominators refer to the magnitude of the vectors.

In this case, since C = A + B is also a unit vector, are you working with an equilateral triangle?
• Dec 2nd 2009, 10:44 PM