Question

Find the length of tangent of $\frac{x^2}{9}+\frac{y^2}{4}=1$ at $(9,4)$.

• A. $14$
• B. $12$
• C. $16$
• D. None of these

Answer 1

The correct option is D None of these

Length of tengent of $(\frac{x^2}{a^2}+\frac{y^2}{b^2}-1)$ at $(x_1,y_1)=\sqrt{E(x_1,y_1)}$

Where $E(x,y)=\frac{x^2}{a^2}+\frac{y^2}{b^2}-1$

Length of tangent at $(9,4)=\sqrt{9+4-1}$

$=\sqrt{13-1}$

$=\sqrt{12}$