DefinitionIn more generally, derivatives can be applied to modelling and calculating variations in a distinct measure such as demand and supply, cost functions (economic derivatives), or rates of gradients of curves (which are essential for solving physics problems on motion), and optimization problems in engineering. They help in finding the points of maxima, minima and points of inflection. For an example: maximize the profit, set the profit function equal to its derivative then find the critical point, to use the second derivative test.