Aspire's Library

A Place for Latest Exam wise Questions, Videos, Previous Year Papers,
Study Stuff for MCA Examinations - NIMCET

Previous Year Question (PYQs)



Let $\vec{a}=2\hat{i}-\hat{j}+\hat{k}$ and $\vec{b}=\lambda\hat{j}+2\hat{k}$, $\lambda\in Z$. Let $\vec{c}=\vec{a}\times\vec{b}$ and $\vec{d}$ be a vector of magnitude $2$ in $yz$-plane. If $|\vec{c}|=\sqrt{53}$, then the maximum possible value of $(\vec{c}\cdot\vec{d})^2$ is:





Solution

$\vec{c}=\vec{a}\times\vec{b} \Rightarrow |\vec{c}|=\sqrt{53}$. Maximum dot when $\vec{d}$ parallel to projection of $\vec{c}$ on yz-plane → $(\vec{c}\cdot\vec{d})_{max}=|\vec{c}|\cdot|\vec{d}|=\sqrt{53}\cdot2$. Square = $4\times53=104$


Online Test Series,
Information About Examination,
Syllabus, Notification
and More.

Click Here to
View More


Online Test Series,
Information About Examination,
Syllabus, Notification
and More.

Click Here to
View More

Ask Your Question or Put Your Review.

loading...