Find 
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
|
|,  if  
7
7
and
3
2
2
a b
a
i
j
k
b
i
j
k
×
= −
+
=
−
+
r
r
r
r 2 Find a unit vector perpendicular to each of the vector 
and
a
b
a
b
+
−
r
r
r
r
, where
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
3
2
2
and
2
2
a
i
j
k
b
i
j
k
=
+
+
= +
−
r
r 3