14 Find the shortest distance between the lines
ˆ
ˆ
ˆ
(
2
)
r
i
j
k
=
+
+
r
 + 
ˆ
ˆ
ˆ
(
)
i
j
k
λ
−
+
 and
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
2
(2
2 )
r
i
j
k
i
j
k
=
−
−
+ µ
+
+
r
15 Find the shortest distance between the lines
1
1
1
7
6
1
x
y
z
+
+
+
=
=
−
   and  
3
5
7
1
2
1
x
y
z
−
−
−
=
=
−
16 Find the shortest distance between the lines whose vector equations are
ˆ
ˆ
ˆ
(
2
3 )
r
i
j
k
=
+
+
r
 + 
ˆ
ˆ
ˆ
(
3
2 )
i
j
k
λ
−
+
and  
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
4
5
6
(2
3
)
r
i
j
k
i
j
k
=
+
+
+ µ
+
+
r
17