Search any question & find its solution
Question:
Answered & Verified by Expert
If â is a unit vector such that $(\bar{x}-\hat{a}) \cdot(\bar{x}+\hat{a})=8$, then $|\bar{x}|=$
Options:
Solution:
1405 Upvotes
Verified Answer
The correct answer is:
3
We have $(\overline{\mathrm{x}}-\hat{\mathrm{a}}) \cdot(\overline{\mathrm{x}}+\hat{\mathrm{a}})=8$
$$
\therefore|\overline{\mathrm{x}}|^2-|\hat{\mathrm{a}}|^2=8 \Rightarrow|\overline{\mathrm{x}}|^2=8+1=9 \Rightarrow|\overline{\mathrm{x}}|=3
$$
$$
\therefore|\overline{\mathrm{x}}|^2-|\hat{\mathrm{a}}|^2=8 \Rightarrow|\overline{\mathrm{x}}|^2=8+1=9 \Rightarrow|\overline{\mathrm{x}}|=3
$$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.