In this chapter, we shall study the direction cosines
and direction ratios of a line joining two points and also
discuss about the equations of lines and planes in space
under different conditions, angle between two lines, two
planes, a line and a plane, shortest distance between two
skew lines and distance of a point from a plane Most of
the above results are obtained in vector form Nevertheless, we shall also translate
these results in the Cartesian form which, at times, presents a more clear geometric
and analytic picture of the situation 11