Find the angle between the vectors 
ˆ
ˆ
2ˆ
3  
i
j
k
−
+
 and 
ˆ
ˆ
ˆ
3
2
i
j
k
−
+
3 Find the projection of the vector ˆ
ˆ
i
−j
 on the vector ˆ
ˆ
i
+j 4 Find the projection of the vector 
ˆ
ˆ
3ˆ
7
i
j
k
+
+
 on the vector 
ˆ
ˆ
ˆ
7
8
i
j
k
−
+