The Fourier cosine transform of a real function is the real part of the full complex Fourier transform,
| 
 
(1)
 
 | |||
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(2)
 
 | 
The Fourier cosine transform  of a function 
 is implemented as FourierCosTransform[f,
 x, k], and different choices of 
 and 
 can be used by passing the optional FourierParameters
 -> 
a,
 b
 option. In this work, 
 and 
.
The discrete Fourier cosine transform of a list  of real numbers can be computed in the Wolfram
 Language using FourierDCT[l].