Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
If the vectors $\hat{\mathrm{i}}-\mathrm{x} \hat{\mathrm{j}}-\mathrm{y} \hat{\mathrm{k}}$ and $\hat{\mathrm{i}}+\mathrm{x} \hat{\mathrm{j}}+\mathrm{y} \hat{\mathrm{k}}$ are orthogonal to
each other, then what is the locus of the point $(\mathrm{x}, \mathrm{y})$ ?
MathematicsVector AlgebraNDANDA 2012 (Phase 1)
Options:
  • A a parabola
  • B an ellipse
  • C a circle
  • D a straight line
Solution:
2427 Upvotes Verified Answer
The correct answer is: a circle
Since both vectors are orthogonal $\therefore$ their dot product is zero.
$\therefore 1(1)+(-x)(x)+(-y)(y)=0$
$\Rightarrow 1-x^{2}-y^{2}=0$
$\Rightarrow x^{2}+y^{2}=1$
Which is a circle.

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.