...the angles, less than 180°, between this line and the positive directions of the X-, Y-, and Z-axes. These angles are called the direction angles of the...cosines are called the direction cosines of the line. Let P, whose coordinates are x, y, and 2, be any point on the line. Let OP = p. Then x = p cos a, y...

...Denote by a, 0, 7 the angles which a directed line makes with the positive directions of the axes of x, y, z respectively. These angles are called the direction...the angles 180° — a, 180° — ft, 180° — y, tfie cosines of which are equal to — cos or, — cos/3, — cosy. THEOREM. DIRECTION COSINES OF A...

...to the respective coordinate axes. The angles which a line OP makes with the axes, ie, 0i = Z POx{ , are called the direction angles of the line, and their cosines are called direction cosines. If the norm N(P), ie, the distance D(OP), is denoted by p, then the direction cosines...