JEE Main & Advanced
Mathematics
Vector Algebra
Question Bank
Scalar triple product and their applications
question_answer
If \[\mathbf{a}=3\mathbf{i}-\mathbf{j}+2\mathbf{k},\] \[\mathbf{b}=2\mathbf{i}+\mathbf{j}-\mathbf{k},\] then \[\mathbf{a}\times (\mathbf{a}\,.\,\mathbf{b})=\] [Karnataka CET 1994]
A) 3a
B) \[3\sqrt{14}\]
C) 0
D) None of these
Correct Answer:
D
Solution :
\[\mathbf{a}\times (\mathbf{a}\,.\,\mathbf{b})\] is not meaningful.