If the vector is represented by coordinates, a=(x1, y1, z1), b=(x2, y2, z2), then a.b=(x1x2+y1y2+z1z2).
These generations of formula (I), get:
The above formula is given by the spatial three-dimensional coordinates, so that z=0 in the coordinates, the calculation formula of the plane vector is obtained. The range of the angle between the two vectors is: [0, π].
When the angle is an acute angle, cos θ>0;
When the angle is an obtuse angle, cos θ < 0.
Comment list ( 0 )