differential calculus

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The mathematics of the variation of a function with respect to changes in independent variables.
• noun The study of slopes of curves, accelerations, maxima, and minima by means of derivatives and differentials.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun calculus The calculus that deals with instantaneous rates of change.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the part of calculus that deals with the variation of a function with respect to changes in the independent variable (or variables) by means of the concepts of derivative and differential