Having taught us the Parshah of Korban Tamid in Tetzaveh, why does the Torah repeat it here?
1.
Ramban #1 (in Pasuk 2, citing Rashi): In Tetzaveh, the Torah is referring spcifically to the eight days of the Milu'im, and here, to future generations.
1
2.
Ramban #2 (in Pasuk 2): In order to list it together with the other Korb'nos Musaf.
2
Ramban: And it is for the same reason that the Torah inserts briefly the Parshah of the Korban Pesach, even though it already discussed it in Sh?mos, chapter 12.