Equations of Tangent and Normal to the Circle
Here we list the equations of tangent and normal for different forms of a circle and also list the condition of tangency for the line to a circle.

The equation of tangent to the circle at is

The equation of normal to the circle at is

The equation of tangent to the circle at is

The condition of tangency for a line to the circle is
and the equation of tangent to the circle is

The equation of tangent to the circle at is

The equation of normal to the circle at is