A) 4
B) 3
C) \[\sqrt{12}\]
D) \[\frac{7}{2}\]
Correct Answer: A
Solution :
We have \[{{a}^{2}}=16\] and \[9{{b}^{2}}={{a}^{2}}(1-{{e}^{2}})\] \[9=16(1-{{e}^{2}})\] So, \[e=\frac{\sqrt{7}}{4}\] Thus, the foci are\[(\pm \sqrt{7},0)\] The radius of required circle \[=\sqrt{{{(\sqrt{7}-0)}^{2}}+{{3}^{2}}}\] \[=\sqrt{7+9}\] \[=4\]You need to login to perform this action.
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