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 x=1-t21+t2 and y=2t1+t2,then dydx is equal to
MathematicsDifferentiationJEE Main
Options:
  • A -yx
  • B yx
  • C -xy
  • D xy
Solution:
1249 Upvotes Verified Answer
The correct answer is: -xy
x=1-t21+t2 and y=2t1+t2

Put t=tanθ in both the equations, we get

x=1-tan2θ1+tan2θ=cos2θ ...(i)

and y=2tanθ1+tan2θ=sin2θ ...(ii)

On differentiating both the eqs.(i) and (ii), we get

dxdθ=-2sin2θ and dydθ=2cos2θ

Therefore, dydx=dydθdxdθ=-cos2θsin2θ=-xy

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.