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 ...

Plotting a graph takes time. Often mathematicians just want to know the key features. These are: shape, location and some key points (such as where the graph crosses the axes or turning points).

Forbes contributors publish independent expert analyses and insights. I help people communicate data clearly with graphs. I recently saw the infographic in Figure 1 and thought to myself, “Another ...