- The document discusses finding the equation of a tangent line to a circle given a point of tangency, as well as finding points of intersection between a line and a circle. - The key steps are to find the center and radius of the circle from its equation, then use properties of tangents (gradient of radius = -1/gradient of tangent) to determine the gradient of the tangent line. - To find intersections, set the line and circle equations equal and solve using substitution or factorizing, looking for real number solutions. If only one solution is found, the line is tangent to the circle.