State the formula for the distance between points (x1,y1)(x_1, y_1)(x1,y1) and (x2,y2)(x_2, y_2)(x2,y2).
A circle is defined as the set of all points that are the same distance from a fixed point called the centre.
Substitute the coordinates of the point into the circle equation and solve for kkk.
When a line and circle equation are combined into a quadratic, the line is a tangent if the quadratic has one repeated root (or the discriminant is zero).
Flashcards for Edexcel A Level Maths Circles, covering the key formulae, methods and definitions you need to recall for Paper 1, Paper 2 and Paper 3. 24 cards drawn from 6.1 Midpoints and Perpendicular Bisectors, 6.2 Equation of a Circle, 6.3 Intersections of Straight Lines and Circles, 6.4 Use Tangent and Chord Properties, and 6.5 Circles and Triangles, matched to the Edexcel A Level Maths (9MA0) specification. Recall questions account for roughly 50% of marks at A Level Maths, so these target the marks you can secure before the paper starts.
