So, for the given vector, we have
a = 1, b = 1 and c = –2 Further, if l, m and n are the direction cosines of the given
vector, then
1
1
2
,
,
  as  | |
6
|
|
|
|
|
|
6
6
6
a
b
c
l
m
n
r
r
r
r
−
=
=
=
=
=
=
r=
r
r
r
Thus, the direction cosines are 
1
1
2
,
,–
6
6
6
⎛
⎞
⎜
⎟
⎝
⎠ 10 5