To calculate the derivative of a function, one must use techniques from the differential branch of calculus. This branch of calculus is related to the integral branch by the first fundamental theorem of calculus: ''differentiation'' (the process of finding a derivative) ''is the reverse process of [[integral|integration]]'' (the process of finding an integral). | To calculate the derivative of a function, one must use techniques from the differential branch of calculus. This branch of calculus is related to the integral branch by the first fundamental theorem of calculus: ''differentiation'' (the process of finding a derivative) ''is the reverse process of [[integral|integration]]'' (the process of finding an integral). |