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TS EAMCET · Maths · Ellipse

If any tangent drawn to the ellipse \(\frac{x^2}{16}+\frac{y^2}{9}=1\) touches one of the circles \(x^2+y^2=\alpha^2\), then the range of \(\alpha\) is

  1. A \(9 \leq \alpha \leq 16\)
  2. B \(16 \leq \alpha \leq 25\)
  3. C \(3 \leq \alpha \leq 4\)
  4. D \(4 \leq \alpha \leq 6\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(3 \leq \alpha \leq 4\)

Step-by-step Solution

Detailed explanation

Tangent to ellipse \(\frac{x^2}{16}+\frac{y^2}{9}=1\) is \(y=mx \pm \sqrt{16m^2+9}\). Distance from origin to tangent to circle \(x^2+y^2=\alpha^2\) is \(\alpha\). \(\alpha = \frac{|\pm \sqrt{16m^2+9}|}{\sqrt{m^2+1}}\). \(\alpha^2 = \frac{16m^2+9}{m^2+1}\).…