##### Wikipedia

**Differintegral**

In fractional calculus, an area of applied mathematics, the **differintegral** is a combined differentiation/ integration operator. Applied to a function ƒ, the *q*-differintegral of *f*, here denoted by

D*f*

is the fractional derivative (if *q* > 0) or fractional integral (if *q* < 0). If *q* = 0, then the *q*-th differintegral of a function is the function itself. In the context of fractional integration and differentiation, there are several legitimate definitions of the differintegral.