Question
Question: The locus of the centre of a circle radius 2 which rolls on the outside of the circle x<sup>2</sup> ...
The locus of the centre of a circle radius 2 which rolls on the outside of the circle x2 + y2 + 3x – 6y – 9 = 0 is –
A
x2 + y2 + 3x – 6y + 5 = 0
B
x2 + y2 + 3x – 6y + 31 = 0
C
x2 + y2 + 3x – 6y + 429 = 0
D
None of these
Answer
x2 + y2 + 3x – 6y + 31 = 0
Explanation
Solution
If centre of the circle which rolls outside the given circle be (h, k), then distance between the centres = sum of radii.