BBC

The equation of a line through two points

The straight line through two points will have an equation in the form \(y = mx + c\). Then, we can find the value of \(c\), the \(y\)-intercept, by substituting the coordinates of one point into the ...
BBC

The equation of the tangent to a circle - Higher

As the tangent is a straight line, the equation of the tangent will be of the form \(y = mx + c\). We can use perpendicular gradients to find the value of \(m\), then use the coordinates of P to find ...
JSTOR Daily

An Elementary Method of Finding Circles of Curvature at Points, Multiple or Other, of a Plane Curve Whose Equation Is Given in Rectangular Coordinates

The Mathematical Gazette is the original journal of the Mathematical Association and it is now over a century old. Its readership is a mixture of school teachers, college and university lecturers, ...