E whakaatu ana te pārōnaki o tētahi pānga tahi i te pāpātanga o te whiti o te taurangi whakawhirinaki i runga anō i tōna taurangi wehe kē. Arā, ko te rōnaki o te kauwhata o taua pānga tahi i tētahi pūwāhi kotahi.
The derivative of a function determines the rate of change of the dependent variable (output variable) in respect of the independent variable (input variable). It is the slope of the graph of the function at a particular point.