For signal u[n],n=0,1,....N-1, show that its DCT coefficients w[k],k=0,1,...N-1
can be computed as follows:
w[k]=sqrt[2(2-del[k])]R{e to the power-j(pi)k/2N v'[k]}where del[k] is
the Kronecker Delta, R denotes the real part of a complex number and
v'[k]is the Unitary DFT coefficient for signal u'[n] belongs to R to
the power 2N defined as follows:
Transpose of(u')=[u[0]u[1].....u[N-1]00...0],i.e u'is the zero padded
version(upto length 2N)of u.

Based on the above derivation, describe steps needed to implement fast
DCT using FFT.