n. any function whose derivative is a given function; it is usually written as a function of the given function as where f(x) is the given function. For example, x², x² + 5, x²- 3, and any function of the form x² + c, where c is a constant, are indefinite integrals of y = 2x. The schema, here x² + c, is usually given as the general form of an indefinite integral, but c (referred to as the constant of integration) is often omitted; the common indefinite integrals listed in Appendix 2 are given in this form. See integral. Compare definite integral. See also antidifferentiate, fundamental theorem of calculus.