The shape has been reflected in the line \(y = 1\). The equation of a straight line graph has the form \(y = mx + c\), where \(m\) is the gradient and \(c\) is where the line crosses the \(y\)-axis.

Microsoft Excel can generate trend lines based on data you provide, and in doing do, calculates the equation of the trend line. This equation can be accessed using Excel's built-in Visual Basic tools.