Direction cosines of a vector


Direction Cosines of a vector

Let be any vector making the angles , and with the positive X-,Y- and Z- axes respectively. Then the cosines of the angles , and are called the direction cosines of the vector . They are denoted by l = cos, m =cos and n = cos. If = (x,y,z) then cos =, cos= and cos = where,, and are the x-,y- and z- component of the unit vector in the direction of the vector .