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So to find the equation of family of circles touching line L at point P(p,q), can i use the same equation taking S to be a circle of radius zero and center at P?

That is, if L is ax+by+c=0 and P is (p,q), then S will be ##(x-p)^2+(y-q)^2=0## and the equation of family of circles will be ##(x-p)^2+(y-q)^2+\lambda (ax+by+c)=0##. Is this correct? such a circle passes through P.