Among the polynomial curves, a quadratic one has 1 bend, a cubic one has typically 2 bends, and so on. These bends are generally called hills or valleys depending on their shapes. The degree of the polynomial curve is determined by the number of bends in the curve, as it is directly proportional to the degree of the equation it represents. This movement indicates the oscillating values on the y axis. In a polynomial trendline, the trendline curve moves upwards and downwards multiple times.
This trendline can be linear or move in various upward and downward directions. It generally measures the change of a particular parameter, like y, with respect to another parameter(like x values). A trendline, as the name suggests, indicates the trend of change of variables in a graph.
