This
is not a great question to be asking.
Think
of the process on the whizz wheel. To get from CAS via EAS to TAS we use
pressure altitude and temperature. To go back from TAS via EAS to CAS we would
again use pressure altitude and temperature. You are correct when you say that
temperature is a factor. However, it is the entry with pressure altitude and
temperature which corrects for density errors (the fact that the ASI is
calibrated to an atmospheric density value of 1225gm/cuM.); we do not use
density altitude because we are correcting for the difference between
1225gm/cuM and actual density.
Please note: we don't write the questions, we only relay the feedback to you.