Question
Find the equation of a circle having centre at point C(–2, 3) and touching the straight line 3x – 4y – 2 = 0.
Solution
Centre of the required circle is C (-2, 3)
Let line AB with equation 3x - 4y - 2 = 0 touches the circle at point L
∴ p = r
where p, is length of perpendicular CL and r is the radius
The equation of circle is:
or
Hence, the equation of circle is: