Returns the radian angle between two vectors.
float angle( vector
vector1, vector vector2)
vector1 is one
of the vectors.
vector2 is the
other vector.
The returned angle is
the shortest angle between the two vectors. The measurement is always
less than 180 degrees.
Example
angle(<<2,-1,1>>,<<1,1,2>>)
Returns 1.0472 radians,
which equals 60 degrees.
