MCQ
Circles ${x^2} + {y^2} - 2x - 4y = 0$ and ${x^2} + {y^2} - 8y - 4 = 0$
  • Touch each other internally
  • B
    Touch each other externally
  • C
    Cuts each other at two points
  • D
    None of these

Answer

Correct option: A.
Touch each other internally
a
(a) ${C_1}(1,\;2),\;{C_2}(0,\;4),\;{R_1} = \sqrt 5 ,\;{R_2} = 2\sqrt 5 $

${C_1}{C_2} = \sqrt 5 $ and ${C_1}{C_2} = \;|{R_2} - {R_1}|$

Hence circles touch internally.

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