the differential of a function English Differential of a function English Boyer (1959 English English English English differential English English English English differential English differential the differential of a function differential English English the differential of a function Courant & John (1999 English English differential English differential English English differential differential English English http://en.wikipedia.org/wiki/Differential_of_a_function http://en.wikipedia.org/wiki/Differential_of_a_function English English English English English