High Quality Content by WIKIPEDIA articles! Real analysis is an area of analysis, which studies concepts such as sequences and their limits, continuity, differentiation, integration and sequences of functions. However, the scope of real analysis is restricted to the real numbers, and this defines the range of tools available. Real analysis is closely related to complex analysis, which studies broadly the same properties of complex numbers. In complex analysis, it is natural to define differentiation via holomorphic functions, which have a number of useful properties, such as repeated differentiability, expressability as power series, and satisfying the Cauchy integral formula.