Graphs of the form \(y = \frac{1}{x}\), \(y = \frac{2}{x}\), \(y = \frac{3}{x}\), etc., are known as reciprocal graphs, and they all have a similar shape: ...

As the tangent is a straight line, the equation of the tangent will be of ... so the gradient of the tangent is the negative reciprocal of the gradient of the radius. This means that the gradient ...