Editing Real analysis (section)

====Fourier series====
{{Main|Fourier series}}
[[Image:Fourier Series.svg|thumb|200px|The first four partial sums of the [[Fourier series]] for a [[Square wave (waveform)|square wave]]. Fourier series are an important tool in real analysis.]]
Fourier series decomposes [[periodic function]]s or periodic signals into the sum of a (possibly infinite) set of simple oscillating functions, namely [[sine wave|sines and cosines]]  (or [[complex exponential]]s). The study of Fourier series typically occurs and is handled within the branch [[mathematics]] > [[mathematical analysis]] > [[Fourier analysis]].