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CBSE Class 12 Mathematics 2026 Main Paper 65/3/2 · Q242 Marksparametric_derivatives

CBSE Class 12 Mathematics 2026 Main Paper 65/3/2 · Question 24 (Continuity And Differentiability)

If \(x=e^{t+1/t}\) and \(y=e^{t-1/t}\), find dy/dx at t=−2.

✅ Step-by-Step Solution

Final Answer: 5e/3.
  1. Differentiate to obtain dx/dt=(1−1/t²)e^(t+1/t) and dy/dt=(1+1/t²)e^(t−1/t).
  2. Divide to get [(t²+1)/(t²−1)]e^(−2/t).
  3. Substitute t=−2 to get 5e/3.

📋 CBSE Stepwise Marking Scheme

  • [0.5 marks] Differentiate to obtain dx/dt=(1−1/t²)e^(t+1/t) and dy/dt=(1+1/t²)e^(t−1/t).
  • [1 mark] Divide to get [(t²+1)/(t²−1)]e^(−2/t).
  • [0.5 marks] Substitute t=−2 to get 5e/3.

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