1. Show that the three lines with direction cosines
are mutually perpendicular.
GIven direction cosines of the three lines;
And we know that two lines with direction cosines and
are perpendicular to each other, if
Hence we will check each pair of lines:
Lines ;
the lines
are perpendicular.
Lines ;
the lines
are perpendicular.
Lines ;
the lines
are perpendicular.
Thus, we have all lines are mutually perpendicular to each other.