SOLUTION: Obtain the condition that lx+my+n =0 may be tangent to the circle x^2+y^2+2gx+2fy+c=0

Question 1085694: Obtain the condition that lx+my+n =0 may be tangent to the circle x^2+y^2+2gx+2fy+c=0
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Let the point of intersection be (u,v).
So then,

and

You know that the slope of the tangent line is equal to the value of the derivative at the intersection point.
Find the derivative using implicit differentiation,

So then at (u,v),

Using the point slope form of a line,

Comparing,

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