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COMEDK · Maths · 26. Differentiation

\(\text { If } x^2+y^2=t+\dfrac{1}{t} \text { and } x^4+y^4=t^2+\dfrac{1}{t^2} \text { then } \dfrac{d y}{d x}=\)

  1. A \(\dfrac{x}{2 y}\)
  2. B \(\dfrac{y}{x}\)
  3. C \(-\dfrac{y}{x}\)
  4. D \(-\dfrac{x}{2 y}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(-\dfrac{y}{x}\)

Step-by-step Solution

Detailed explanation

Given \(x^2 + y^2 = t + \dfrac{1}{t}\) and \(x^4 + y^4 = t^2 + \dfrac{1}{t^2}\). Squaring the first equation: \((x^2 + y^2)^2 = (t + \dfrac{1}{t})^2\) \(x^4 + y^4 + 2x^2y^2 = t^2 + \dfrac{1}{t^2} + 2\) Substituting \(x^4 + y^4 = t^2 + \dfrac{1}{t^2}\) into the expanded equation:…