This does depend on how your DCT has been defined. The essentialOriginally Posted bymalibupete

connection is if you assume that therealsignal is symmetric about 0, and

extend it to include the negative time components (at large positive

times as the signal is assumed periodic) then the imaginary components

of the DFT will be zero, and the real components will contain the DCT.

The Wikipedia article on the DCT discusses this WikiDCT

RonL