JEE Main 20252 AprilMorning Shift
- Exam
- JEE Main
- Year
- 2025
- Date
- 2 April
- Shift
- Morning Shift
- Subject
- Mathematics
- Chapter
- Hyperbola
JEE Main 2025 · 2 April · Morning Shift · Mathematics · Hyperbola
Let one focus of the hyperbola H: x^2 a^2 - y^2 ~b^2 =1 be at ( 10...
Let one focus of the hyperbola be at \mathrm{x}=\frac{9}{\sqrt{10}}l9 is equal to:
Options
- A14
- B15
- C16
- D12
Correct answer
C. 16
Step-by-step solution
\begin{aligned} & \mathrm{ae}=\sqrt{10} \text{\text{ and } } \frac{\mathrm{a}}{\mathrm{e}}=\frac{9}{10} \\ & \Rightarrow \mathrm{a}^2=9 \text{ and } \mathrm{e}=\frac{\sqrt{10}}{3} \\ & \text{ Now } \quad \begin{aligned} & (\mathrm{ae})^2=\mathrm{a}^2+\mathrm{b}^2 \\ & 10=9+\mathrm{b}^2 \Rightarrow \mathrm{ b}^2=1 \\ & \\ & \ell=\frac{2 \mathrm{ b}^2}{\mathrm{a}}=\frac{2(1)}{3} \\ \Rightarrow & 9\left(\mathrm{e}^2+\ell\right) \\ & =9\left(\frac{10}{9}+\frac{2}{3}\right) \\ & =10+6 \\ & =16\end{aligned}\end{aligned}$