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TS EAMCET · Maths · Application of Derivatives

If the curves \(\frac{x^2}{4}+\frac{y^2}{9}=1\) and \(\frac{x^2}{16}-\frac{y^2}{k}=1\) cut each other orthogonally, then \(k=\)

  1. A 144
  2. B -9
  3. C 25
  4. D -21
Verified Solution

Answer & Solution

Correct Answer

(D) -21

Step-by-step Solution

Detailed explanation

We have, \[ \frac{x^2}{4}+\frac{y^2}{9}=1 \text { and } \frac{x^2}{16}-\frac{y^2}{k}=1 \] On solving these equation, we get \[ x^2=\frac{144+16 k}{36+k} \text { and } y^2=\frac{-27 k}{36+k} \] Now, \(\quad \frac{x^2}{4}+\frac{y^2}{9}=1\)…