Vector Algebra
Cross Product and Triple Product
nta_pyq_2023_apr
Grade 12
Question:
$\vec{d}\perp\vec{a}=2\hat{i}+7\hat{j}-\hat{k}$ and $\vec{b}=3\hat{i}+5\hat{k}$, $\vec{c}\cdot\vec{d}=12$. Then $(-\hat{i}+\hat{j}-\hat{k})\cdot(\vec{c}\times\vec{d})$ is equal to
Step-by-Step Solution
Key Concept: $\vec{d}=\lambda(\vec{a}\times\vec{b})$. Compute $\vec{c}\times\vec{d}$. Use scalar triple product.
$44$.
Correct Answer: 2