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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def s2dctmat(nfilt,ncep,freqstep):
 """Return the 'legacy' not-quite-DCT matrix used by Sphinx"""

    melcos = numpy.empty((ncep, nfilt), 'double')
    for i in range(0,ncep):
        freq = numpy.pi * float(i) / nfilt
        melcos[i] = numpy.cos(freq * numpy.arange(0.5, float(nfilt)+0.5, 1.0, 'double'))
    melcos[:,0] = melcos[:,0] * 0.5
    return melcos