JEE Main & Advanced
Sample Paper
JEE Main Sample Paper-24
question_answer
If \[\vec{a}=5\,\vec{i}-\vec{j}+\vec{k}\,;\vec{b}=2\hat{i}-3\hat{j}-\hat{k}\,;\,\vec{c}=-3\hat{i}+\hat{j}+\hat{k}\]and \[\vec{d}=2\vec{j}+\vec{k}\], then the value of \[\vec{d}.\left( \vec{a}\times \left\{ \vec{b}\times (\vec{c}\times \vec{d}) \right\} \right)\] equals
A) 98
B) 99
C) 100
D) 102
Correct Answer:
A
Solution :
Given expression \[=\left[ \vec{a}\,\vec{c}\,\vec{d} \right]\left( \vec{b}.\vec{d} \right)\]