- Exam
- JEE Main
- Year
- 2024
- Date
- 1 February
- Shift
- Morning Shift
- Subject
- Mathematics
- Chapter
- Circle
JEE Main 2024 · 1 February · Morning Shift · Mathematics · Circle
Let C: x ^ 2 + y ^ 2 = 4 and C ^ ' : x ^ 2 + y ^ 2 - 4 + 9 = 0 be...
Options
- A
- B
- C
- D
Correct answer
D.
Step-by-step solution
Given:
So, centre and radius of are \left(0, 0\right)\text{and}{r}_{1} = 2{C}^{'}: {x}^{2} + {y}^{2} - 4\lambdax + 9 = 0{C}^{'} are \left(2\lambda, 0\right){r}_{2} = \sqrt{4{\lambda}^{2} - 9}⇒ \left|{r}_{1} - {r}_{2}\right|
4{\lambda}^{2} < 4 + 4{\lambda}^{2} - 9 + 4\sqrt{4{\lambda}^{2} - 9}⇒ 5 < 4\sqrt{4{\lambda}^{2} - 9}\left\{{\lambda}^{2} \ge \dfrac{9}{4} \cup \left[\dfrac{3}{2},\infty\right)</p><p>⇒ \dfrac{25}{16} < 4{\lambda}^{2} - 9⇒ \dfrac{169}{64} < {\lambda}^{2}⇒ \dfrac{169}{64} < {\lambda}^{2}⇒ \lambda \in \left(- \infty, - \dfrac{13}{8}\right) . . . \left(ii\right),
\cup \left(\dfrac{13}{8}, \infty\right)⇒ \lambda \in R - \left[\dfrac{13}{8}, \dfrac{13}{8}\right]
As per question - \dfrac{13}{8}b =\dfrac{13}{8}
required point is \left(8a + 12, 16b - 20\right) with satisfies option .