Question

Find the length of sub-tangent of hyperbola $\frac{x^2}{25}-\frac{y^2}{16}=1$ at $(6,4)$

• A. $2$
• B. $\frac{11}{6}$
• C. $\frac{13}{6}$
• D. None of these

Answer 1

The correct option is B $\frac{11}{6}$

Length of sub-tangent $=x_1-\frac{a^2}{x_1}$

simply put $x_1=6$ and $a^2=25$

Length of sub-tangent $=6-\frac{25}{6}$

$=\frac{11}{6}$