Question
Question: The equation of the circle which touches x-axis and whose centre is (1, 2), is –...
The equation of the circle which touches x-axis and whose centre is (1, 2), is –
A
x2 + y2 – 2x + 4y + 1 = 0
B
x2 + y2 – 2x – 4y + 1 = 0
C
x2 + y2 + 2x + 4y + 1 = 0
D
x2 + y2 + 4x + 2y + 4 = 0
Answer
x2 + y2 – 2x – 4y + 1 = 0
Explanation
Solution
Centre (1, 2) ; radius = 2
equation of circle (x – 1)2 +(y – 2)2 = (2)2
x2+y2–2x – 4y + 1 = 0